JPH08236823A - Superconducting radiation detector and method of manufacturing the same - Google Patents

Abstract

(57) [Summary] [Purpose] The present invention relates to a superconducting radiation detector and a manufacturing method thereof.
And a Ta superconducting radiation detector with excellent energy resolution
Device with high reproducibility and complicated manufacturing process
Ta superconducting radiation detector with excellent position resolution
To form [Structure] Energy of Ta and Nb is formed on a single crystal silicon substrate 1.
Lugie gap Δ_TaAnd Δ _NbRelationship with Δ_Ta<Δ_NbBecomes
From the Nb base layer 2, the Ta base layer 3, and the Al layer 4
Bottom electrode is formed, and AlO_xT via the barrier layer 5
The energy gap relationship between a and Nb is Δ_Ta> Δ_NbTona
Upper part composed of Nb counter layer 6 and Ta counter layer 7
Provide electrodes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superconducting radiation detecting apparatus and a method for manufacturing the same, and more particularly to a superconducting radiation detecting apparatus and a superconducting radiation detecting apparatus having improved energy resolution and radiation collecting ability used in the field of physical property analysis or medical field. The present invention relates to a manufacturing method.

[0002]

2. Description of the Related Art Conventionally, radiation typified by X-rays has been widely used in the field of physical property analysis or medical field. At that time, a semiconductor radiation detection apparatus typified by silicon is used as an X-ray detection apparatus. in use.

However, the energy resolution of a semiconductor radiation detector using silicon is 6 keV incident X
The maximum is 150 eV with respect to the line, which is the limit for performing more detailed physical property analysis.

This energy resolution (relative resolution P)
Is dependent on the energy ε required to generate electron-hole pairs, where E is the energy of the incident X-ray and F is the Fano factor, P = 2.355 × (ε × F × E) ^1/2 .. represented by formula (1). The Fano factor F is X of the energy E.
When the number of electron-hole pairs generated when a line is incident is N and the one enclosed by <> is the average value thereof, <
(N- <N>) ² > / <N> is a parameter that indicates the degree to which the fluctuation of the number of excited electrons becomes smaller than the fluctuation of the Poisson distribution, and if the Poisson distribution is followed, F = 1, When not complying, F <1 (Yoichi Koshi, Kimitaka Sato, "Energy dispersive X-ray analysis", The Spectroscopic Society of Japan, Academic Publishing Center). The electronic - energy epsilon necessary to generate the hole pairs, when the semiconductor forbidden band width of the radiation detecting apparatus _{E g, ε = 2.8 × E} g + (0.5~1.0 ) EV ... Represented by formula (2) (CA Klein, J. Appl. Ph)
ys. , Vol. 39, p. 2090, 1968).

For example, in a radiation detector using a silicon pn junction with E _g = 1.16 eV, the energy ε required to generate electron-hole pairs is several eV (3.748 to
Since it is 4.248 eV and the measured value is 3.76 eV), 6
The number N of electron-hole pairs excited by incident X-rays of keV
₁ is N ₁ = 6000 / 3.76≈1.6 × 10 ³ , which is considerably small, but in the case of a semiconductor radiation detection apparatus, it is about 100 by applying an electric field from the outside to the pn junction. Since electrons and holes can be collected at a value close to%, the energy resolution is 150 eV (6 k
eV) is achieved, and this energy resolution of 150 eV approaches the theoretical limit (approximately 100 eV) at the measured value of the Fano factor F of 0.08.

Therefore, since the energy resolution P is proportional to ε ^1/2 as shown in the above equation (1), it is necessary to use a material having a small ε in order to enhance the energy resolution. Then, in order to reduce ε, it is sufficient to reduce E _g as shown in the above equation (2).
_{Even if g} is reduced, ε is 0.5 to 1.0e of the additional constant term.
Since it cannot be lower than V, the energy resolution P
There is a limit to the improvement of.

On the other hand, in the field of superconductivity, it is known that the energy gap in the Josephson junction is about 3 orders of magnitude smaller than the band gap of a semiconductor, and a radiation detector using this superconductor. In the case of (1), the energy resolution of several eV, that is, the resolution 10 times higher than that of the semiconductor radiation detection apparatus is expected. Therefore, various radiation detection apparatuses using this superconductor have been proposed.

In the superconducting radiation detecting apparatus, Cooper pairs are excited instead of the electron-hole pairs in the semiconductor radiation detecting apparatus to generate quasiparticles, and the energy required to generate one quasiparticle is generated. Although ε is not represented by the above formula (2), in order to realize a superconducting radiation detector with high energy resolution, (1) the number of quasi-particles generated, as in the case of the semiconductor radiation detector. Is required, and (2) the generated quasiparticles can be collected without being lost on the way.

For example, in the case of a radiation detector using a Josephson junction, the number of quasiparticles excited by an incident X-ray of 6 keV has an energy ε required for excitation of 3.0 me.
When V is set, N ₁ = 6000 / 3.0 meV = 2.0 × 10 ⁶ pieces, which is theoretically expected to be increased by about three digits as compared with the semiconductor radiation detection apparatus using silicon.

However, in the case of a superconducting radiation detector using tin (Sn) as a superconductor, an incident X of 6 keV is applied.
The energy resolution of 37 eV with respect to the line, that is, about 5 times the energy resolution of the silicon semiconductor radiation detection apparatus, is obtained, and only about 1/10 of the theoretically expected energy resolution of several eV is obtained. No. (W. Rothmund. Et. Al., “X-RAY
DETECTION BY SUPERCONDUCT
ING TUNNEL JUNCTIONS ", edi
ted by A. Barone (World Sci
Entific, Singapore), pp. 63,
1991).

The reason why the expected value cannot be obtained in the superconducting radiation detecting apparatus using tin is that the electric field cannot enter in the superconductor, so that the electric field is applied like the semiconductor to collect the quasi-particles. Cannot be done, and therefore
It is considered that the collection efficiency of quasi-particles is poor even though the number of quasi-particles generated is large.

The superconducting radiation detecting apparatus using tin is not only inferior in energy resolution to the theoretically predicted value, but also used as a bonding material for Josephson integrated circuits until the early 1980s. Similar to Pb) bonding, it has a fatal defect that it is weak against aging and thermal cycles of room temperature-cryogenic temperature-room temperature, that is, it has a fatal defect that the barrier deteriorates and shorts due to the thermal cycle. It was not a radiation detector.

Also, many experiments have been conducted to construct a radiation detector using a Nb / AlO _x -Al / Nb junction which is widely used in superconducting digital integrated circuits and which is stable against aging and thermal cycles. Although it is carried out by the institute, the value obtained is lower than the energy resolution of the radiation detection device using tin.

In recent years, various proposals have been made to improve the drawbacks of the superconducting radiation detecting apparatus using tin or Nb, but the generated quasi-particles are collected without loss during the process. For this reason, it is considered that a longer quasiparticle life is advantageous, so we investigated the quasiparticle life of various typical superconducting materials. Table 1 shows the results.

[0015]

[Table 1]

Table 1 also shows the X-ray absorption ability, that is, the radiation stopping ability.
It shows the layer thickness necessary to absorb 90% of incident X-rays of eV, and the smaller this value is, the more
It shows that the X-ray absorption capacity is high. This X-ray absorptivity is a characteristic required when X-rays are incident from the back surface of the single crystal silicon substrate, and the X-ray absorptivity below is evaluated by the reciprocal of the film thickness shown in Table 1. It is a thing.

Now, referring to Table 1, the quasi-particle life of various superconducting materials will be examined. As is clear from Table 1, the quasi-particle lifetime τ ₀ of Al is 438 ns (10 ^-9
sec) is two orders of magnitude longer than other materials, but X
The linear absorptivity is 300 μm, which is one order of magnitude lower than that of other materials, and the quasi-particle life τ ₀ of Sn (tin) is 2.30 ns.
Is about one digit larger than Nb of 0.149, and X
Since the linear absorption capacity is about 1.5 times that of Nb, it is an optimal material for the superconducting radiation detection device from this point, but as described above, it is fatal that it is weak in thermal cycle, that is, thermal stability. There is a physical defect.

On the other hand, as a material having high thermal stability, Ta is used.
And the quasi-particle lifetime τ of Ta ₀Is 1.78 ns
And larger than other materials such as Nb and Pb, and X
As a superconductor, it has high quasi-particle life due to its high line absorption capacity.
Radiation with long and thermally stable Ta
A detector is being tried.

This conventional superconducting radiation detector is shown in FIG.
Will be described with reference to. See FIG. 13. In this conventional superconducting radiation detecting apparatus, a Ta base layer 28, a barrier layer 29, and a Ta counter layer 30 are deposited on a single crystal silicon substrate 27 by a sputtering method and then patterned to form a predetermined area. Josephson junction is formed and covered with a protective insulating film 31 such as SiO ₂ and then T
The Ta wiring layer 32 electrically connected to the a base layer 28 and the Ta counter layer 30 is provided. Like this, T
The superconducting radiation detection apparatus using a has good thermal stability and has a relatively long quasi-particle life. Therefore, by using Ta, a high energy resolution and a practical superconducting radiation detection apparatus can be obtained. The device is obtained.

Further, as a detector for physical property analysis or medical application, not only high energy resolution but also position resolution is an important factor. Therefore, it is expected that the radiation detection elements are arrayed to have a position detection ability. A conventional superconducting radiation detecting apparatus having such a position detecting ability will be described with reference to FIGS. 14 and 15.

Referring to FIG. 14A, first, a Ta radiation blocking film 33 is deposited on the back surface of the single crystal silicon substrate 27 by a sputtering method, and then a Ta base layer 28 and a barrier layer 29 are formed on the front surface side of the single crystal silicon substrate 27. , And Ta counter layer 30 are also deposited by sputtering.

Next, as shown in FIG. 14 (b), using the first photoresist mask 31 as a mask, a T film is formed by RIE (reactive ion etching).
After patterning the radiation blocking film 33, Ta
KO using the pattern of the radiation blocking film 33 as a mask
Etching the single crystal silicon substrate 27 with an H aqueous solution,
An X-ray entrance hole 35 into which X-rays enter is formed.

Referring to FIG. 14C, the Ta counter layer 30 is first etched by the RIE method using the second photoresist mask 36, and then the barrier layer 29 is etched by the ion milling method using Ar. By doing so, the area of the Josephson junction is defined to have a predetermined size.

See FIG. 15D. Then, using the third photoresist mask 37, Ta is used.
The base layer 28 is etched again by the RIE method,
The size of the Ta base layer 28 is defined. 15E, the SiO ₂ film is used as the protective insulating film 38 to cover the Josephson junction.

Next, as shown in FIG. 15F, contact holes for the Ta base layer 28 and the Ta counter layer 30 are formed using a fourth photoresist mask (not shown), and then the Ta layer is sputtered over the entire surface. And then patterned by using a fifth photoresist mask (not shown) to form a Ta wiring layer 39.
a The radiation detector is completed.

The remaining portion of the Ta radiation blocking film 33 provided on the back surface of the single crystal silicon substrate 27 acts as an X-ray shielding film because Ta has a very high X-ray absorbing ability as shown in Table 1. Since X-rays are transmitted only through the X-ray entrance hole 35, X-rays from other than the X-ray entrance hole 35 do not enter the Josephson junction, and the position detection accuracy is improved.

[0027]

However, as shown in FIG.
In the conventional Ta superconducting radiation detector shown in
There is a problem that a radiation detector having good reproducibility and good element characteristics cannot be obtained. That is, Ta shown in Table 1 above has a body-centered cubic (bcc) structure and a phase transition temperature (T _c ) of 4.47 ° K, but the Ta crystal structure is affected by the underlying substrate. In a normal deposition process, a tetragonal (Tet) having a phase transition temperature (T _c ) of 0.5 ° K is easily used.
A thin film having a (ragonal) structure is easily formed.

The Ta of the tetragonal structure is the phase transition temperature (T
_{Since c} ) is 0.5 ° K, which is lower than the liquid helium temperature of 4.2 ° K, it was difficult to form a cryogenic environment for operating as a superconducting radiation detection device. Further, in order to avoid the formation of Ta having a tetragonal structure, the substrate temperature is set to 3
Although it may be heated to about 00 ° C., heating of the substrate causes disorder of the bonding interface, so that good element characteristics cannot be obtained.

In the conventional Josephson junction structure,
Since there is no mechanism for confining the generated quasiparticles, there is a drawback that the energy resolution is not improved despite the long quasiparticle lifetime.

On the other hand, in the other conventional superconducting radiation detecting apparatus shown in FIGS. 14 and 15, there is a problem that the position resolution cannot be sufficiently increased because a sufficient degree of integration cannot be obtained. That is, the position resolution depends on the distance between the adjacent X-ray incident holes, but in the past, since the plane orientation of the single crystal silicon substrate was used without being sufficiently aware, the (100) plane orientation is generally used. A single crystal silicon substrate was used.

See FIG. 16A. When this single crystal silicon substrate is etched using a KOH solution to form an X-ray entrance hole, an etching hole having a shape depending on the plane orientation, which is a so-called etch pit, is formed. , For example, the thickness of 400 μm (1
In the (00) plane orientation single crystal silicon substrate 40, 10
0 to form an opening matching the Josephson junction × 100 [mu] m ² is at the interface between Ta radiation blocking layer, must be an opening of 900 × 900 .mu.m ^2, for position resolution Dead There is a problem that it becomes a space and the position resolution is not improved.

In order to solve this problem, the thickness of the single crystal silicon substrate may be made thin. However, if it is made too thin, damage to the substrate during handling becomes a problem, and the current ordinary polishing technique is used. Since the thinning is limited to about 100 μm, in order to form a 100 × 100 μm ² opening corresponding to the Josephson junction in the (100) plane-oriented single crystal silicon substrate 40 having a thickness of 100 μm,
At the interface with the Ta radiation blocking film, 300 × 300μ
Since it is necessary to provide an opening of m ² , the uncertainty of position resolution is still large.

As another means, if dry etching having anisotropic etching characteristics is used instead of wet etching using a KOH solution, it is possible to form an opening having a substantially vertical wall surface. Therefore, although the problem of position resolution is solved for a while, in order to form an X-ray entrance hole penetrating a single crystal silicon substrate having a thickness of 100 to 400 μm by using dry etching having a slow etching rate, It is an unrealistic means that requires a huge amount of time.

Therefore, according to the present invention, a Ta superconducting radiation detecting apparatus which has an excellent energy resolution and is formed into an array with excellent reproducibility and which has an excellent positional resolution without complicating the manufacturing process. Is intended to be formed.

[0035]

FIG. 1 is an explanatory view of the principle configuration of the present invention, and the means for solving the problems in the present invention will be described with reference to FIG. Note that FIG. 1 (a)
1A is a cross-sectional view of a basic element structure of a superconducting radiation detection apparatus of the present invention, and FIG. 1B shows an energy gap structure taken along the alternate long and short dash line AA ′ of FIG. Is.

1 (a) and 1 (b), the present invention provides a superconducting radiation detecting apparatus, in which a lower electrode composed of an Nb base layer 2, a Ta base layer 3 and an Al layer 4 is provided on a substrate 1. N via the AlO _x barrier layer 5
An upper electrode composed of the b counter layer 6 and the Ta counter layer 7 is provided, and the relationship between the Ta and Nb energy gaps Δ _Ta and Δ _Nb in the lower electrode is Δ _Ta <Δ _Nb ,
Further, it is characterized in that the relationship of the energy gap between Ta and Nb in the upper electrode is Δ _Ta > Δ _Nb . In addition,
Reference numeral 10 in FIG. 1A is a protective insulating film.

Further, according to the present invention, as the upper electrode structure, the Al layer, the Nb counter layer 6, and the
It is characterized by using a three-layer structure in which the Ta counter layer 7 is laminated.

The present invention also relates to a superconducting radiation detector.
On the substrate 1, the Nb base layer 2, Ta base layer 3,
And a lower electrode composed of the Al layer 4 is provided, and AlO_xBari
W counter layer and Ta counter layer 7 through the layer 5
And the Ta in the lower electrode
And Nb energy gap Δ_TaAnd Δ_NbRelationship with Δ _Ta
<Δ_NbIs characterized in that.

Further, in the present invention, as the upper electrode structure, the Al layer, the W counter layer, and the Ta layer are sequentially arranged from the barrier layer 5 side.
It is characterized by using a three-layer structure in which the counter layers 7 are laminated.

Further, the present invention is characterized in that the wiring layer 12 is an Nb layer having an energy gap relationship between the Ta base layer 3 and the Ta counter layer 7 of Δ _Ta <Δ _Nb .

In the method for manufacturing a superconducting radiation detecting device of the present invention, the Nb layer 2 of the lower electrode is formed on the single crystal silicon substrate 1 under the film forming condition that the phase transition temperature is 9.25 ° K.
While sputtering the Nb layer 6 of the upper electrode at a lower applied power density and a slower deposition rate than the Nb layer 2 of the lower electrode, the energy gap of the Nb layer 6 of the upper electrode is Nb of the lower electrode. It is characterized in that the energy gap is smaller than that of the layer 2.

The present invention also relates to a superconducting radiation detector.
On the surface of the substrate, the Nb base layer, the Ta base layer,
And a lower electrode composed of an Al layer is provided, and AlO_xbarrier
The Nb counter layer and the Ta counter layer.
An upper electrode is provided, and Ta and Nb in the lower electrode are
Energy gap of_TaAnd Δ_NbRelationship with Δ_Ta<Δ _Nb
And the energy of Ta and Nb in the upper electrode
The gap relationship is Δ_Ta> Δ_NbAnd the back of the board
A radiation blocking film is provided on the substrate, and the radiation blocking film and the substrate are exposed.
A feature is that a ray incident hole is provided.

Further, the present invention is a superconducting radiation detecting apparatus, wherein a Nb base layer, a Ta base layer,
Further, a lower electrode made of an Al layer is provided, an upper electrode made of a W counter layer and a Ta counter layer is provided via an AlO _x barrier layer, and energy gaps Δ _Ta and Δ _Nb of Ta and Nb in the lower electrode are provided. In addition to the relation Δ _Ta <Δ _Nb , a radiation blocking film is provided on the back surface of the substrate, and a radiation entrance hole is provided in the radiation blocking film and the substrate.

Further, according to the present invention, one Josephson junction is formed for one lower electrode composed of the Nb base layer and the Ta base layer, or the Nb base layer and the T base layer are formed.
It is characterized in that a plurality of Josephson junctions are formed with respect to one lower electrode composed of a base layer.

Further, according to the present invention, the plane orientation of the substrate is (1
10) plane single crystal silicon substrate is used, a Ta film is used as a radiation blocking film, and the Ta film is covered with an Al film. Further, the lower electrode, the barrier layer, and the upper electrode are silicon oxide film and silicon. It is characterized by being sequentially covered with a nitride film.

[0046]

By providing the Ta base layer 3 via the Nb base layer 2 and the Ta counter layer 7 via the Nb counter layer 6 on the substrate, the phase transition temperature having a body-centered cubic structure is obtained. It is possible to form the Ta base layer 3 and the Ta counter layer 7 having a temperature of 4.47 ° K with good reproducibility, and by providing the AlO _x barrier layer 5 via the Al layer 4, good interface characteristics are obtained. A barrier layer can be formed.

The relationship between the Ta and Nb energy gaps Δ _Ta and Δ _Nb in the lower electrode is Δ _Ta <Δ _Nb ,
Moreover, by setting the relationship of the energy gap between Ta and Nb in the upper electrode to be Δ _Ta > Δ _Nb , a confinement mechanism by the energy barrier is formed, so that the collection efficiency of quasi-particles can be improved.

This state will be described with reference to FIG. See FIG. 2. FIG. 2 shows an energy barrier structure when X-rays are incident on the structure shown in FIG. 1B in a biased state. In the Ta base layer 3, an electron pair 14 is generated by an incident X-ray 13. The quasi-particles 15 are excited and generated, and the generated quasi-particles tunnel through the AlO _x barrier layer 5 to generate T
It is taken out from the Nb wiring layer 12 through the a counter layer 7.

In this case, the quasi-particles 15 directed toward the Nb base layer 2 are repelled by the energy barrier resulting from the difference in energy gap between the Nb base layer 2 and the Ta base layer 3 and are directed toward the AlO _x barrier layer 5 side. Opposite, Al
The O _x barrier layer 5 is tunneled to be taken out from the Nb wiring layer 12 via the Ta counter layer 7, and the collection efficiency of the quasi-particles 15 is improved.

Further, by using a three-layer structure in which the Al layer, the Nb counter layer 6 and the Ta counter layer 7 are sequentially laminated from the barrier layer 5 side as the upper electrode structure, the barrier can be maintained in higher quality. it can.

Further, by providing the Ta base layer 3 on the substrate 1 via the Nb base layer 2 and by providing the Ta counter layer 7 via the W counter layer,
T having a body-centered cubic structure and a phase transition temperature of 4.47 ° K
The a base layer 3 and the Ta counter layer 7 can be formed with good reproducibility, and by providing the AlO _x barrier layer 5 via the Al layer 4, it is possible to form a barrier layer having good interface characteristics. Out.

[0052] Also, the relationship between the energy gap delta _Ta and delta _Nb and Ta and Nb in the lower electrode delta _Ta <delta _Nb becomes, and, the relationship between the energy gap of Ta and W in the upper electrode delta _Ta> and delta _W Therefore, the confinement mechanism by the energy barrier is formed and the collection efficiency of the quasi-particles can be improved.

As the upper electrode structure, an Al layer, a W counter layer, and a Ta counter layer 7 are sequentially arranged from the barrier layer 5 side.
By using a three-layer structure in which the barrier layers are stacked, it is possible to keep the barrier quality higher.

Further, by using the Nb layer having the energy gap relationship Δ _Ta <Δ _Nb as the wiring layer 12, the quasi-particles can be more efficiently confined.

Further, the energy gap of the Nb layer is changed by changing the deposition conditions of the Nb base layer 2 of the lower electrode and the Nb counter layer 6 of the upper electrode, and the quasi-particles are efficiently confined by using the same material. The structure can be formed.

Further, a radiation blocking film is provided on the back surface of the substrate,
By providing the radiation entrance hole in the radiation blocking film and the substrate, scattered light of the radiation incident on another position is not erroneously detected, so that the position detection capability of the superconducting radiation detecting device when arrayed is improved. Can be increased.

Further, by forming one Josephson junction for one lower electrode, it is possible to enhance the position detection ability, while forming a plurality of Josephson junctions for one lower electrode. As a result, the output from a plurality of Josephson junctions can be used, and thus the radiation collection efficiency can be improved.

See FIG. 16B. Further, when the single crystal silicon substrate 41 having a plane orientation of (110) plane is used as the substrate, it is also shown in FIG. Since the wall surface of the radiation entrance hole can be made substantially vertical, the density of providing the radiation entrance hole can be increased, and therefore, the position detectability of the superconducting radiation detection device when arrayed can be improved.

Further, by using the same Ta film as the Ta film forming the Josephson junction as the radiation blocking film, the structure of the deposition apparatus can be simplified, and further,
By sequentially covering the lower electrode, the barrier layer, and the upper electrode with a silicon oxide film and a silicon nitride film, the silicon oxide film and the silicon nitride film function as an etching resistant protective film when forming a radiation entrance hole, It also functions as a surface protective film when forming the wiring layer.

[0060]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 3 to 5 are explanatory views of a manufacturing process of a first embodiment of the present invention. See FIG. 3A. First, DC is formed on the (110) plane single crystal silicon substrate 1.
An applied current of 1.
Nb of 50 nm at a deposition rate of 2.5 nm / sec under the conditions of 5 A, applied voltage 300 V, and Ar gas pressure of 1.3 Pa.
After depositing the base layer 2, a lower electrode composed of a 200 nm Ta base layer 3 and a 20 nm Al layer 4 is deposited.

In this case, the deposition conditions for the Nb base layer 2 are:
Select the condition that the phase transition temperature becomes 9.25 ° K,
In order to obtain an Nb layer having a large phase transition temperature, that is, a large energy gap, and the thickness thereof may be about 2 to 5 nm when used as a simple buffer layer, the superconductivity of Nb is A thickness of 10 to 100 nm is necessary to form the quasi-particle confinement structure by positively utilizing it, and it may be 100 to 300 nm. Further, the thickness of the Ta base layer 3 may be 50 nm or more, and the upper limit is that which absorbs X-rays in the Ta base layer 3. Therefore, the upper limit is determined by the energy of the X-rays to be detected. In this case, it may be 10 μm. Furthermore, the thickness of the Al layer 4 may be in the range of 5 to 50 nm, but there is no problem if it is in the range of 50 to 100 nm.

Then, the surface of the Al layer 4 is oxidized to form an AlO _x barrier layer 5 having a thickness of about 10 Å (1 nm), and then an applied current of 0.3 A is similarly applied by using the DC magnetron sputtering method. , Applied voltage 250
V, Ar gas pressure 1.3 Pa, and deposition rate 0.5 nm
The Nb counter layer 6 having a phase transition temperature of 3.0 ° K is deposited to a thickness of 5 nm and then the Ta counter layer 7 having a thickness of 20 nm is deposited to form an upper electrode.

The AlO _x barrier layer 5 is the Al layer 4
Since it is formed by the oxidation of, a uniform barrier layer without pinholes is formed, and the deposition conditions of the Nb counter layer 6 are as follows.
By selecting a low deposition rate condition that is smaller than the energy gap of the Nb base layer 2 and smaller than that of the Ta counter layer 7, an Nb layer having a low phase transition temperature, that is, a small energy gap is formed. Although it acts as a buffer layer for forming a Ta film of a cubic crystal, it is necessary to prevent it from serving as an energy barrier for quasi-particles. Since the material having a small energy gap has a low phase transition temperature, the Nb counter layer 6 is made of liquid H.
Since it does not become a superconductor at e temperature, its thickness is 10 to reduce the influence on the device characteristics such as proximity effect.
The thickness of the Ta counter layer 7 is preferably in the range of 10 to 500 nm.

See FIG. 3B. Then, using the first photoresist mask 8 as a mask, RIE (reactive ion) is performed under the conditions of a pressure of 7 Pa using CF ₄ + 5% O ₂ gas and an applied power of 50 W. Etching) is performed to etch the Ta counter layer 7 and the Nb counter layer 6 and then ion milling using Ar is performed to etch the AlO _x barrier layer 5 and the AO _x barrier layer 5.
The I layer 4 is etched to determine the junction area of the Josephson junction.

Next, as shown in FIG. 4C, after removing the first photoresist mask,
By using the newly provided second photoresist mask 9 as a mask, reactive ion etching is performed under the same conditions of a pressure of 7 Pa using CF ₄ + 5% O ₂ gas and an applied power of 50 W. Base layer 3 and Nb
The base layer 2 is etched to determine the size of the base layer.

Next, as shown in FIG. 4D, after removing the second photoresist mask,
The protective insulating film 10 made of a SiO ₂ film having a thickness of 600 nm or more is deposited by the RF sputtering method. As the protective insulating film may be a silicon nitride film in addition to the SiO ₂ film, it may also be used a two-layer film of SiO ₂ film and a silicon nitride film.

Next, as shown in FIG. 5E, a newly provided third photoresist mask 11 is provided.
CHF ₃ + 30% O ₂ gas was used as a mask 7
The protective insulating film 10 is etched by the reactive ion etching method under the pressure of Pa and the applied power of 50 W to form contact holes for the upper electrode and the lower electrode.

Next, as shown in FIG. 5F, after removing the third photoresist mask,
An Nb layer of 800 nm thickness is deposited by depositing an Nb layer and etching by a reactive ion etching method using a new photoresist mask (not shown) as a mask.
The b wiring layer 12 is formed, and the superconducting radiation detection device is completed.

Here, the reason why the Nb layer is used as the underlying buffer layer for depositing the Ta layer will be explained. As mentioned in the problem to be solved by the invention, the deposited T layer is deposited.
Since the crystal structure of the a layer has a strong underlying dependency, the underlying dependency of the various buffer layers examined will be described first.

On a single crystal silicon substrate having a (100) plane orientation, directly through an Al (face-centered cubic structure: fcc) buffer layer, and through Zr (hexagonal close-packed structure: hcp), N
b (body-centered cubic structure: bcc), and W (b
A 200 nm Ta film is deposited using DC magnetron sputtering via cc). The thickness of the buffer layer is all 10 nm.

Next, an X-ray diffraction test was performed on these samples. When Ta was directly deposited on the substrate, the difference in lattice constant between silicon having a diamond structure and Ta having a body-centered cubic structure was large. Crystal structure (Tetragonal)
It was found that a Ta film having a body centered cubic structure was obtained when the buffer layer was interposed. However, from the X-ray diffraction intensity, A with a weak diffraction intensity
In the case of using the 1 buffer layer, 4.2 ° K (liquid He
It showed no superconductivity when measured in electrical resistance at
The r buffer layer, the Nb buffer layer, and the W buffer layer exhibited superconductivity at 4.2 ° K.

Therefore, Zr or W may be used if only used as a buffer layer,
In order to form an energy barrier structure for confining quasi-particles as shown in FIG. 1B, Zr (phase transition temperature: 0.55 ° K) and W (phase transition temperature: 0) are used as the lower electrode. It is necessary to use Nb (phase transition temperature: 9.25 ° K) having a larger energy gap than that of 0.012 ° K. That is, from the BCS theory, the energy gap delta superconductors and the phase transition temperature and k _B the T _c and Boltzmann constant, since it is Δ = 1.76k _B · T _c, as the phase transition temperature is greater , Because the energy gap becomes large.

On the other hand, in order to form a confinement structure also in the upper electrode, as a base film of the Ta counter layer 7,
A base film with a small energy gap is required, but N
The b film does not show a significant underlayer dependence in the crystal structure and the phase transition temperature, but the energy gap of the film obtained differs depending on the deposition conditions. Therefore, by utilizing this characteristic, the Ta counter layer 7 Also as a base film, T of the lower electrode
By using the same Nb as the base film of the a base layer 3, the structure of the sputtering apparatus can be simplified.

By using an Nb film having a phase transition temperature of 9.25 ° K as the wiring layer 12, the Nb wiring layer 12 having a large energy gap with respect to the Ta counter layer 7 of the upper electrode serves as an energy barrier. Therefore, the effect of confining the quasi-particles can be further enhanced.

Although the (110) plane single crystal silicon substrate 1 is used as the substrate in the first embodiment, the (100) plane single crystal silicon substrate may be used in this case. Alternatively, another substrate such as glass may be used. Further, as an upper electrode, an A of about 40 to 50 Å is provided between the AlO _x barrier layer 5 and the Nb counter layer 6.
A three-layer structure of Al / Nb / Ta may be formed by interposing the l layer, and in this case, the interface characteristics of the barrier are further enhanced.

Next, a second embodiment of the present invention will be described with reference to FIG. 6 (a) is a sectional view of the superconducting radiation detecting apparatus of the second embodiment, and FIG.
Shows the energy gap structure along the chain line connecting AA ′ in FIG. 6 (a), and FIG.
[FIG. 4] shows IV characteristics (current-voltage characteristics) of the superconducting radiation detecting apparatus of the second embodiment.

See FIG. 6A. The second embodiment is different only in that the Nb counter layer 6 in the first embodiment is replaced with the W counter layer 16 and the thickness of each layer is different. The other manufacturing conditions and manufacturing process order are the same as those of FIGS.

First, on the (110) plane single crystal silicon substrate 1, a DC magnetron sputtering method was used.
An Nb base layer 2 of 100 nm was deposited at a deposition rate of 2.5 nm / sec under the conditions of an applied current of 1.5 A, an applied voltage of 300 V, and an Ar gas pressure of 1.3 Pa.
A bottom electrode consisting of a Ta base layer 3 of 50 nm and an Al layer 4 of 50 nm is deposited. The Nb base layer 2 has a thickness of 10 to 300 nm, and the Ta base layer 3 has a thickness of 50 nm.
nm or more, and the thickness of the Al layer 4 may be in the range of 5 to 100 nm.

Then, the surface of the Al layer 4 is oxidized to form an AlO _x barrier layer 5 having a thickness of about 10 Å (1 nm), and then an applied current of 1.5 A is similarly applied by using the DC magnetron sputtering method. , Applied voltage 300
2.5 nm under the conditions of V and Ar gas pressure of 1.3 Pa
The W counter layer 16 is deposited to a thickness of 20 nm at a deposition rate of / sec, and then a Ta counter layer 7 having a thickness of 200 nm is deposited to form an upper electrode. Subsequent etching steps and film forming steps are performed in the same manner as in the first embodiment to complete the superconducting radiation detector.

In this case, since W does not show a significant underlayer dependency in the crystal structure like Nb, the W counter layer 16 acts as a buffer layer for forming a body-centered cubic Ta film. However, its phase transition temperature is as low as 0.012 ° K. Therefore, it does not serve as an energy barrier for quasi-particles due to its small energy gap. Further, since the W counter layer 16 is a buffer layer for forming a Ta film, it is desirable that the thickness is thinner, for example, 10 nm or less. 20 because it does not have a bad influence
It may be less than or equal to nm, and further less than or equal to 100 nm.

See FIG. 6B. The energy gap structure of the superconducting radiation detecting apparatus of the second embodiment is almost the same as the energy gap structure of the superconducting radiation detecting apparatus of the first embodiment, and the upper electrode The junction characteristics are almost the same, except that the Nb counter layer 6 on the side is replaced by the W counter layer 16 having a smaller energy gap.

See FIG. 6C. In FIG. 6C, the area of the Josephson junction is 50 × 50 μm.
are those in which the the I-V characteristic of the superconducting radiation detector of m ² and the _{Ta / W / AlO x -Al /} Ta / Nb structure was measured at 0.5 ° K, a steep rise of the gap voltage, yet It was found that the dark current was also very small, and it was confirmed that a good Josephson junction was formed.

Next, with reference to FIGS. 7 to 10, a superconducting radiation detecting apparatus having a position detecting ability according to a third embodiment of the present invention will be described. Although one Josephson junction is shown in the figure, in reality, these are arranged in an array.

Referring to FIG. 7A, first, on the back surface of the (110) plane single crystal silicon substrate 1, 5 μm was formed by using the DC magnetron sputtering method.
m Ta radiation blocking film 17 and 50 nm Al protective film 1
8 is deposited. It should be noted that Ta is a good radiation blocking film because it has a high X-ray absorbing ability as is clear from Table 1, and the thickness of this Ta radiation blocking film 17 is appropriate depending on the energy of the radiation to be detected. Although the thickness is selected, it is generally in the range of 1 to 10 μm, and the Al protective film 18 has a thickness of 1 in the subsequent step.
In order to prevent the Ta radiation blocking film 17 from being etched due to disappearance of the photoresist mask in the reactive ion etching process which takes several tens of minutes when forming the X-ray entrance hole in the Ta radiation blocking film 17 of 10 μm. Is something
The thickness may be 10 to 100 nm.

Then, on the opposite surface of the single crystal silicon substrate 1, using a DC magnetron sputtering method under the conditions of an applied current of 1.5 A, an applied voltage of 300 V, and an Ar gas pressure of 1.3 Pa. After depositing a 50 nm Nb base layer 2 at a deposition rate of 5 nm / sec, 200
A lower electrode composed of a Ta base layer 3 of 20 nm and an Al layer 4 of 20 nm is deposited.

In this case, the deposition conditions for the Nb base layer 2 are also
The phase transition temperature is selected to be 9.25 ° K. The thickness thereof may be about 2 to 5 nm when used as a simple buffer layer. A thickness of 10 to 100 nm is necessary for positively forming a quasi-particle confinement structure, and may be 100 to 300 nm. Further, the thickness of the Ta base layer 3 may be 50 nm or more, and the upper limit is that which absorbs X-rays in the Ta base layer 3, so that it is determined by the energy of X-rays to be detected.
In the case of high energy, it may be 10 μm. Further, the thickness of the Al layer 4 may be in the range of 5 to 50 nm, but there is no problem even if it is set to 50 to 100 nm.

Then, the surface of the Al layer 4 is oxidized to form an AlO _x barrier layer 5 having a thickness of about 1 nm, and then a DC magnetron sputtering method is used to apply an applied current of 0.3 A and an applied voltage. An upper electrode composed of a 5 nm Nb counter layer 6 and a 200 nm thick Ta counter layer 7 is deposited at a deposition rate of 0.5 nm / sec under the conditions of 250 V and Ar gas pressure of 1.3 Pa.

The deposition condition of the Nb counter layer 6 in this case is also as follows from the energy gap of the Nb base layer 2.
In addition, a low deposition rate condition smaller than that of the Ta counter layer 7 may be selected, and its thickness is preferably 10 nm or less in order to improve device characteristics.
The thickness of the counter layer 7 may be in the range of 10 to 500 nm.

Then, referring to FIG. 7B, reactive ion etching is performed under the conditions of a pressure of 7 Pa using CF ₄ + 5% O ₂ gas and an applied power of 50 W, using the first photoresist mask 8 as a mask. By doing so, the Ta counter layer 7 and the Nb counter layer 6 are etched, and then the AlO _x barrier layer 5 and the Al layer 4 are etched by ion milling using Ar to determine the junction area of the Josephson junction.

Next, as shown in FIG. 8C, after removing the first photoresist mask,
By using the newly provided second photoresist mask 9 as a mask, reactive ion etching is performed under the same conditions of a pressure of 7 Pa using CF ₄ + 5% O ₂ gas and an applied power of 50 W. Base layer 3 and Nb
The base layer 2 is etched to determine the size of the base layer.

Next, as shown in FIG. 8D, after removing the second photoresist mask,
By the RF sputtering method, 600 nm thick S
An iO ₂ film 19 and a 200 nm silicon nitride film 20 are deposited. The SiO ₂ film 19 may have a thickness of 600 nm or more, and the silicon nitride film 20 may be used.
Is a thickness enough to function as a protective mask for preventing the SiO ₂ film 19 from being etched in a wet etching process using a KOH solution for forming an X-ray entrance hole in the single crystal silicon substrate 1 in a subsequent process. The thickness may be 10 to 300 nm here.

Next, as shown in FIG. 9E, the third photoresist mask 2 is formed on the back surface of the substrate.
1 is provided and an opening for forming the X-ray incident hole 22 is formed in the Al protective film 18 by the ion milling method using Ar. Then, using this Al protective film 18 as a mask, CF ₄ + 5% O ₂ Reactive ion etching is performed under the conditions of a pressure of 50 Pa using gas and an applied power of 100 W to etch the Ta radiation blocking film 17 to form an opening for forming the X-ray entrance hole 22. The etching rate at this time is 100 nm / min.

Next, as shown in FIG. 9F, the entire substrate is dipped in a KOH solution to form an X-ray entrance hole 22 whose wall surface is substantially vertical in the single crystal silicon substrate 1. In this case, since the wall surface is substantially vertical, the X-ray entrance holes 2 of the arrayed superconducting radiation detecting device 2
2 can be provided close to each other, and the position detectability is improved.

See FIG. 10G. Next, using the fourth photoresist mask 23 as a mask, a reactive ion etching method was performed under the conditions of a pressure of 25 Pa using CHF ₃ + 30% O ₂ gas and an applied power of 100 W. Then, the silicon nitride film 20 and the SiO ₂ film 19 are etched at an etching rate of 30 nm / min to form contact holes 24 for the upper and lower electrodes.

Then, as shown in FIG. 10H, after removing the fourth photoresist mask,
An Nb layer of 800 nm thickness is deposited by depositing an Nb layer and etching by a reactive ion etching method using a new photoresist mask (not shown) as a mask.
By forming the b wiring layer 25, a superconducting radiation detecting device having a high position detecting ability is completed.

In the third embodiment as well, the AlO _x barrier layer 5 and the Nb counter layer 6 are used as the upper electrodes.
And an Al layer of about 40 to 50 Å is interposed between
A three-layer structure of / Nb / Ta may be used. In this case,
The barrier interface properties are further enhanced. Further, by using an Nb film having a phase transition temperature of 9.25 ° K as the wiring layer 25, the Nb wiring layer 25 having a large energy gap with respect to the Ta counter layer 7 of the upper electrode serves as an energy barrier. The particle confinement effect can be further enhanced.

Also in the third embodiment, the first
Although a Josephson junction including a lower electrode, a barrier layer, and an upper electrode similar to that of the above example is formed, in this case, a Ta film is used only for the lower electrode that absorbs X-rays, and the upper electrode is used. 5 to 50 nm, preferably 20 n from the barrier layer side
m Al layer and 10-500 nm, preferably 20 n
It is also possible to adopt a two-layer structure in which m m Nb counter layers are sequentially deposited.

Next, with reference to FIG. 11, a superconducting radiation detection device having a position detecting ability in which a W counter layer is provided between an AlO _x barrier layer and a Ta counter layer according to the fourth embodiment of the present invention. The device will be described. Although one Josephson junction is shown in the figure, in reality, these are arranged in an array.

See FIG. 11. The fourth embodiment is different only in that the Nb counter layer 6 in the third embodiment is replaced with the W counter layer 16 and that the thickness of each layer is different. The manufacturing conditions, the manufacturing process order, and the like are the same as those in FIGS. 7 to 10, and thus will be briefly described.

Referring to FIG. 11, first, on the back surface of the (110) plane single crystal silicon substrate 1, 5 μm was formed by the DC magnetron sputtering method.
m Ta radiation blocking film 17 and 50 nm Al protective film 1
8 is deposited. Also in this case, the thickness of the Ta radiation blocking film 17 may be generally in the range of 1 to 10 μm, and the Al protective film 18 may be in the range of 10 to 100 nm.

Then, on the opposite surface of the single crystal silicon substrate 1, using a DC magnetron sputtering method under the conditions of an applied current of 1.5 A, an applied voltage of 300 V and an Ar gas pressure of 1.3 Pa. After depositing a 100 nm Nb base layer 2 at a deposition rate of 5 nm / sec, 30
A bottom electrode consisting of a 0 nm Ta base layer 3 and a 50 nm Al layer 4 is deposited. The Nb base layer 2 has a thickness of 10 to 300 nm, and the Ta base layer 3 has a thickness of 5 nm.
The thickness of the Al layer 4 may be 0 nm or more, and may be in the range of 5 to 100 nm.

Next, the surface of the Al layer 4 is oxidized to form an AlO _x barrier layer 5 having a thickness of about 1 nm, and then the same DC magnetron sputtering method is used to apply an applied current of 1.5 A and an applied voltage. 20 nm W counter layer 16 at a deposition rate of 2.5 nm / sec and 200 nm under the conditions of 300 V and Ar gas pressure of 1.3 Pa.
An upper electrode consisting of Ta counter layer 7 of thickness 1 is deposited. The thickness of the W counter layer 16 is preferably 100 nm or less, more preferably 20 nm or less in order to improve the device characteristics, and the Ta counter layer 7 has a thickness of 10 to 500 nm. Good.

Then, the superconducting radiation detecting apparatus having a high position detecting ability is completed through the same steps as the steps of FIGS. 7B to 10H.

Also in the fourth embodiment, the AlO _x barrier layer 5 and the W counter layer 16 are used as the upper electrodes.
And an Al layer of about 40 to 50 Å is interposed between
A three-layer structure of W / Ta may be used, and in this case, the interface characteristics of the barrier are further improved. Further, by using an Nb film having a phase transition temperature of 9.25 ° K as the wiring layer 25, the Nb wiring layer 25 having a large energy gap with respect to the Ta counter layer 7 of the upper electrode serves as an energy barrier. The particle confinement effect can be further enhanced.

In addition, in the fourth embodiment as well, the second
Although a Josephson junction including a lower electrode, a barrier layer, and an upper electrode similar to that of the above example is formed, in this case, a Ta film is used only for the lower electrode that absorbs X-rays, and the upper electrode is used. 5 to 100 nm, preferably 50 from the barrier layer side
nm Al layer and 10-500 nm, preferably 20
A two-layer structure in which 0 nm Nb counter layers are sequentially deposited may be used.

Next, a fifth embodiment of the present invention will be described with reference to FIG. See FIG. 12. FIG. 12 is a cross-sectional view of elements of a superconducting radiation detection device in which a plurality of Josephson junctions are formed for one lower electrode to improve X-ray collection efficiency. Although it shows two radiation detection element parts, in reality, these are arranged in an array,
The manufacturing process and the material used are substantially the same as in the third embodiment.

That is, first, on the back surface of the (110) plane single crystal silicon substrate 1, a Ta radiation blocking film 17 having a thickness of 1 to 10 μm, preferably 5 μm, and a thickness of 10 to 100 nm were used by the DC magnetron sputtering method. 50nm
The Al protective film 18 is deposited. Next, an applied current of 1.5 A and an applied voltage of 30 A were applied on the surface of the single crystal silicon substrate 1 on the opposite side by using the DC magnetron sputtering method.
2.5 n under the condition of 0 V and Ar gas pressure of 1.3 Pa
10 to 100 nm at a deposition rate of m / sec, preferably 50 n
m Nb base layer 2 is deposited and then 50 nm to 10 nm
μm, preferably 200 nm Ta base layer 3, and 5
Deposit a bottom electrode consisting of ˜50 nm, preferably 20 nm of Al layer 4.

Then, the surface of the Al layer 4 is thermally oxidized.
AlO with a thickness of about 1 nm _xBarrier layer 5 is formed
After that, similarly, DC magnetron sputtering method
Applied current 0.3A, applied voltage 250V, Ar
With a gas pressure of 1.3 Pa, a stack of 0.5 nm / sec
Nb counter with a product speed of 10 nm or less, preferably 5 nm
Layer 6 and a thickness of 10-500 nm, preferably 20 nm
An upper electrode made of Ta counter layer 7 is deposited.

Then, using the first photoresist mask as a mask, reactive ion etching is performed under the conditions of a pressure of 7 Pa using CF ₄ + 5% O ₂ gas and an applied power of 50 W, to thereby form a Ta counter layer. 7 and Nb
After etching the counter layer 6, the AlO _x barrier layer 5 and the Al layer 4 are etched by ion milling using Ar to form a plurality of Josephson junctions having a predetermined area.

Then, after removing the first photoresist mask, using the newly provided second photoresist mask as a mask, CF ₄ + 5% O ₂ gas was used for a pressure of 7 Pa and an applied power. The Ta base layer 3 and the Nb base layer 2 are etched by performing reactive ion etching under the condition of 50 W to determine a common base layer size for a plurality of Josephson junctions.

Then, after removing the second photoresist mask, 600 n is formed by RF sputtering.
SiO ₂ film 19 having a thickness of m or more and 10 to 300 nm,
A 200 nm silicon nitride film 20 is preferably deposited. Then, a third photoresist mask having a plurality of openings corresponding to the Josephson junction is provided on the back surface side of the substrate, and Al is formed by an ion milling method using Ar.
An opening for forming the X-ray entrance hole 22 is formed in the protective film 18, and then C is formed by using the Al protective film 18 as a mask.
In order to form the X-ray entrance hole 22 by etching the Ta radiation blocking film 17 by performing reactive ion etching under the condition of a pressure of 50 Pa using F ₄ + 5% O ₂ gas and an applied power of 100 W. To form an opening.

Then, the entire substrate is dipped in a KOH solution to form an X-ray entrance hole 22 whose wall surface is substantially vertical in the single crystal silicon substrate 1. Then, by using the fourth photoresist mask as a mask, a pressure of 25 Pa using CHF ₃ + 30% O ₂ gas and a reactive ion etching method under the conditions of an applied power of 100 W were used to obtain about 30 nm.
Silicon nitride film 20 and Si at an etching rate of 1 / min.
The O ₂ film 19 is etched to form contact holes for the upper electrode and the lower electrode.

Next, after removing the fourth photoresist mask, an Nb layer having a thickness of 800 nm is deposited, and the new photoresist mask is used as a mask to perform etching by the reactive ion etching method.
By forming the b wiring layer 25, a superconducting radiation detection device having high X-ray collection efficiency is completed.

A plurality of Josephson junctions and corresponding X-ray entrance holes 2 are provided for this one base layer, that is, the lower electrode.
When a two-dimensional array of superconducting radiation detectors having two is configured, the positional resolution in one direction is reduced, but since X-rays can be detected at a plurality of Josephson junctions, incident X-rays on one lower electrode 26 The X-ray collection efficiency, that is, the sensitivity, is increased because the irradiation amount of is increased.

In this case, in order to improve the X-ray collection efficiency, it is theoretically possible to provide one large Josephson junction without providing a plurality of Josephson junctions.
Then, it becomes difficult to form a uniform barrier layer without pinholes in such a large area. Therefore, a plurality of Josephson junctions having a small area are provided to increase the total junction area. .

In the fifth embodiment as well, the third embodiment is used.
A Josephson junction including a lower electrode, a barrier layer, and an upper electrode similar to that of the above example is formed, but in this case also, the Ta film is used only for the lower electrode that absorbs X-rays and the upper electrode is used. 5 to 50 nm, preferably 20 n from the barrier layer side
m Al layer and 10-500 nm, preferably 20 n
It is also possible to adopt a two-layer structure in which m m Nb counter layers are sequentially deposited.

Also in the fifth embodiment, the second
Alternatively, as in the fourth embodiment, the Nb counter layer 6 may be replaced with a W counter layer, and in that case, the change of each condition associated with the replacement is the same as that of the second or fourth embodiment. .

Further, in each of the above-mentioned embodiments, the area of the Josephson junction is not mentioned except for the second embodiment, and the theoretical size is not limited.
The size is about 50 μm ^{2 to} 100 × 100 μm ² . Furthermore, although the thickness of the single crystal silicon substrate is not mentioned in each of the above embodiments, it is usually 400.
A silicon wafer of μm is used, and if necessary, it may be thinned to about 100 μm by polishing.

In the third and fifth embodiments, the X-ray entrance hole is opened after the Josephson junction is patterned. However, the X-ray entrance hole is opened like the conventional example. After that, the Josephson junction may be patterned, and in that case, the silicon nitride film is not always necessary.

[0120]

According to the present invention, a Ta film having a phase transition temperature of 4.47 ° K can be obtained with good reproducibility by using the Nb layer or the W layer as the underlayer of the Ta layer. , A superconducting radiation detector excellent in energy resolution can be provided, and as a substrate (110)
By using a single-crystal silicon substrate having a plane, it is possible to increase the element density when arrayed, that is, the X-ray entrance hole density, and thus to provide an arrayed superconducting radiation detection device with excellent positional resolution. Further, by providing a plurality of Josephson junctions for one lower electrode, it is possible to provide an arrayed superconducting radiation detector with high X-ray collection efficiency.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a principle configuration of the present invention.

FIG. 2 is an explanatory view of the operation of the present invention.

FIG. 3 is an explanatory diagram of a manufacturing process up to the middle of the first embodiment of the present invention.

FIG. 4 is an explanatory diagram of a manufacturing process up to the middle of FIG. 3 and subsequent steps of the first embodiment of the present invention.

FIG. 5 is an explanatory diagram of the manufacturing process of FIG. 4 and subsequent steps of the first embodiment of the present invention.

FIG. 6 is an explanatory diagram of a second embodiment of the present invention.

FIG. 7 is an explanatory view of the manufacturing process up to the middle of the third embodiment of the present invention.

FIG. 8 is an explanatory view of the manufacturing process up to the middle of FIG. 7 and subsequent steps of the third embodiment of the present invention.

FIG. 9 is an explanatory diagram of a manufacturing process up to the middle of FIG. 8 and subsequent steps of the third embodiment of the present invention.

FIG. 10 is an explanatory diagram of the manufacturing process after FIG. 9 of the third embodiment of the present invention.

FIG. 11 is a cross-sectional view of a superconducting radiation detection device of a fourth embodiment of the present invention.

FIG. 12 is a cross-sectional view of a superconducting radiation detection device of a fifth embodiment of the present invention.

FIG. 13 is a sectional view of a conventional superconducting radiation detection device.

FIG. 14 is an explanatory view of a manufacturing process up to the middle of another conventional superconducting radiation detecting apparatus.

FIG. 15 is an explanatory view of the manufacturing process of another conventional superconducting radiation detecting apparatus after FIG.

FIG. 16 is an explanatory diagram of the plane orientation dependence of the cross-sectional shape of the X-ray entrance hole.

[Explanation of symbols]

1 Single Crystal Silicon Substrate 2 Nb Base Layer 3 Ta Base Layer 4 Al Layer 5 AlO _x Barrier Layer 6 Nb Counter Layer 7 Ta Counter Layer 8 First Photoresist Mask 9 Second Photoresist Mask 10 Protective Insulating Film 11 Third Photoresist mask 12 Nb wiring layer 13 incident X-ray 14 electron pair 15 quasi-particle 16 W counter layer 17 Ta radiation blocking film 18 Al protective film 19 SiO ₂ film 20 silicon nitride film 21 third photoresist mask 22 X-ray incident Hole 23 Fourth photoresist mask 24 Contact hole 25 Nb wiring layer 26 Incident X-ray 27 Single crystal silicon substrate 28 Ta base layer 29 Barrier layer 30 Ta counter layer 31 Protective insulating film 32 Ta wiring layer 33 Ta radiation blocking film 34th 1 photoresist mask 35 X-ray entrance hole 36 The photoresist mask 37 third photoresist mask 38 protective insulating film 39 Ta wiring layer 40 (100) plane single crystal silicon substrate 41 (110) plane single crystal silicon substrate

Claims (11)

[Claims] 1. A Nb base layer, a Ta base layer, and
And a lower electrode made of an Al layer is provided, an upper electrode made of an Nb counter layer and a Ta counter layer is provided via an AlO _x barrier layer, and Ta in the lower electrode is provided.
And the energy gap between _Nb and Δ _Ta and Δ _Nb is Δ _Ta
<Δ _Nb , and Ta and Nb in the upper electrode
Superconducting radiation detecting apparatus, wherein the relationship between the energy gap is Δ _Ta> Δ _Nb. 2. The superconducting radiation detecting apparatus according to claim 1, wherein an Al layer is interposed between the barrier layer and the Nb counter layer as the upper electrode structure. 3. A Nb base layer, a Ta base layer, and
And, providing a lower electrode made of Al layer, through the AlO _x barrier layer, provided with an upper electrode made of W counters layer and Ta counters layer, and the energy gap delta _Ta and delta _Nb and Ta and Nb in the lower electrode The relation of Δ _Ta <
A superconducting radiation detector characterized by being Δ _Nb . 4. The superconducting radiation detecting apparatus according to claim 3, wherein as the upper electrode structure, an Al layer is interposed between the barrier layer and the W counter layer. 5. The Ta base layer and T as a wiring layer
a The energy gap relationship with the counter layer is Δ _Ta <Δ
_The superconducting radiation detecting apparatus according to claim 1, wherein an Nb layer which is Nb is used. 6. The Nb base layer of the lower electrode is sputtered on the single crystal silicon substrate under the film forming condition of the phase transition temperature of 9.25 ° K.
The counter layer is sputtered at a lower applied power density and a lower deposition rate than the Nb base layer to produce the N
2. The method for manufacturing a superconducting radiation detector according to claim 1, wherein the energy gap of the b counter layer is smaller than the energy gap of the Nb base layer and the energy gap of the Ta counter layer. 7. A lower electrode composed of an Nb base layer, a Ta base layer, and an Al layer is provided on the surface of the substrate, and AlO _x
Through the barrier layer, an upper electrode provided consisting of Nb counter layer and Ta counter layer, and the relationship between the energy gap delta _Ta and delta _Nb and Ta and Nb in the lower electrode and delta _Ta <delta _Nb, also, Ta and N in the upper electrode
A superconducting radiation detecting device characterized in that the relationship of the energy gap of b is Δ _Ta > Δ _Nb , a radiation blocking film is provided on the back surface of the substrate, and a radiation entrance hole is provided in this radiation blocking film and the substrate. 8. A lower electrode composed of an Nb base layer, a Ta base layer, and an Al layer is provided on the surface of the substrate, and AlO _x
An upper electrode composed of a W counter layer and a Ta counter layer is provided via a barrier layer, and T in the lower electrode is provided.
The energy gap between a and Nb Δ _Ta and Δ _Nb
A superconducting radiation detecting device, characterized in that _Ta < _ΔNb , a radiation blocking film is provided on the back surface of the substrate, and a radiation entrance hole is provided in the radiation blocking film and the substrate. 9. The superconducting radiation detecting apparatus according to claim 7, wherein one Josephson junction is formed with respect to one lower electrode composed of the Nb base layer and the Ta base layer. 10. The superconducting radiation detecting apparatus according to claim 7, wherein a plurality of Josephson junctions are formed on one lower electrode composed of the Nb base layer and the Ta base layer. 11. A single crystal silicon substrate having a plane orientation of (110) is used as the substrate, a Ta film is used as the radiation blocking film, and the Ta film is covered with an Al film. 11. The superconducting radiation detector according to claim 7, wherein the electrode, the barrier layer, and the upper electrode are sequentially covered with a silicon oxide film and a silicon nitride film.