JPH06164004A - Superconductive device - Google Patents
Superconductive deviceInfo
- Publication number
- JPH06164004A JPH06164004A JP43A JP33358592A JPH06164004A JP H06164004 A JPH06164004 A JP H06164004A JP 43 A JP43 A JP 43A JP 33358592 A JP33358592 A JP 33358592A JP H06164004 A JPH06164004 A JP H06164004A
- Authority
- JP
- Japan
- Prior art keywords
- metal
- semiconductor
- junction
- superconductor
- work function
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000004065 semiconductor Substances 0.000 claims abstract description 37
- 239000002887 superconductor Substances 0.000 claims abstract description 36
- 229910052751 metal Inorganic materials 0.000 claims abstract description 33
- 239000002184 metal Substances 0.000 claims abstract description 33
- 239000000758 substrate Substances 0.000 claims abstract description 13
- 229910052746 lanthanum Inorganic materials 0.000 claims abstract description 11
- 229910052784 alkaline earth metal Inorganic materials 0.000 claims abstract description 10
- 150000001342 alkaline earth metals Chemical class 0.000 claims abstract description 10
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 claims abstract description 10
- 229910052783 alkali metal Inorganic materials 0.000 claims description 16
- 150000001340 alkali metals Chemical class 0.000 claims description 16
- 230000004888 barrier function Effects 0.000 abstract description 20
- 150000002739 metals Chemical class 0.000 abstract description 5
- 238000002834 transmittance Methods 0.000 abstract description 5
- 238000009792 diffusion process Methods 0.000 abstract description 2
- 150000002500 ions Chemical class 0.000 abstract description 2
- 239000007787 solid Substances 0.000 abstract description 2
- 239000002585 base Substances 0.000 description 18
- 239000010408 film Substances 0.000 description 12
- 239000011734 sodium Substances 0.000 description 12
- 229910002367 SrTiO Inorganic materials 0.000 description 7
- 238000010586 diagram Methods 0.000 description 7
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 6
- 239000013078 crystal Substances 0.000 description 6
- 239000002245 particle Substances 0.000 description 5
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 4
- 239000010931 gold Substances 0.000 description 3
- 229910052700 potassium Inorganic materials 0.000 description 3
- 229910052701 rubidium Inorganic materials 0.000 description 3
- 229910052710 silicon Inorganic materials 0.000 description 3
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 229910052791 calcium Inorganic materials 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000005566 electron beam evaporation Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 229910052708 sodium Inorganic materials 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- 238000007740 vapor deposition Methods 0.000 description 2
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 229910052779 Neodymium Inorganic materials 0.000 description 1
- 229910052777 Praseodymium Inorganic materials 0.000 description 1
- 229910052772 Samarium Inorganic materials 0.000 description 1
- 229910052788 barium Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052792 caesium Inorganic materials 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000010884 ion-beam technique Methods 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- 238000003475 lamination Methods 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
Landscapes
- Superconductor Devices And Manufacturing Methods Thereof (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は超電導デバイスに関
し、特に半導体と超電導体との接合の改良に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superconducting device, and more particularly to improving the junction between a semiconductor and a superconductor.
【０００２】[0002]
【従来の技術】半導体と超電導体の接合を用いたデバイ
スとして超電導トランジスタが知られている。コレクタ
・ベース間接合に酸化物超電導体と半導体との接合を用
いたデバイスを本出願人は先に提案している（特願平３
−２２４５６５号に詳しい）。2. Description of the Related Art A superconducting transistor is known as a device using a junction between a semiconductor and a superconductor. The applicant has previously proposed a device using a junction between an oxide superconductor and a semiconductor for the junction between the collector and the base (Japanese Patent Application No. Hei 3).
-Detailed in No. 224565).
【０００３】この提案した方法は、単結晶ＳｒＴｉＯ3
にＮｂを０．０８重量％から０．５重量％の範囲でドー
プすると、ＳｒＴｉＯ3は酸化物ｎ型半導体となるこ
と、そして、このＮｂドープのＳｒＴｉＯ3はペロブス
カイト構造であるという性質を用いて、Ｂａ1-xＫxＢｉ
Ｏ3（ここに０．２＜ｘ＜０．５）（以下、ＢＫＢＯと
略記する。）膜をエピタキシャル成長させるものであ
る。このことを利用した低エネルギー型超電導ベースト
ランジスタを図６に示す。この超電導ベーストランジス
タは、Ｎｂを０．０８重量％以上０．５重量％以下ドー
プした単結晶ＳｒＴｉＯ3からなる酸化物半導体をコレ
クタ領域１０として用い、このコレクタ領域１０上にス
パッタ法によりＢＫＢＯ組成の超電導薄膜からなるベー
ス領域１１が形成される。そして、このベース領域１１
上に絶縁膜１２を形成し、エミッタ領域となる、例えば
Ａｕ（金）電極１３を蒸着により形成している。The proposed method is based on single crystal SrTiO 3
When Nb is doped in the range of 0.08 wt% to 0.5 wt%, SrTiO 3 becomes an oxide n-type semiconductor, and this Nb-doped SrTiO 3 has a perovskite structure. , Ba 1-x K x Bi
An O 3 (here, 0.2 <x <0.5) (hereinafter abbreviated as BKBO) film is epitaxially grown. A low-energy superconducting base transistor utilizing this is shown in FIG. In this superconducting base transistor, an oxide semiconductor made of single crystal SrTiO 3 doped with Nb in an amount of 0.08 wt% or more and 0.5 wt% or less is used as a collector region 10, and a BKBO composition having a BKBO composition is formed on the collector region 10. A base region 11 made of a superconducting thin film is formed. Then, this base region 11
An insulating film 12 is formed on top, and, for example, an Au (gold) electrode 13 to be an emitter region is formed by vapor deposition.
【０００４】[0004]
【発明が解決しようとする課題】ところで、半導体上に
超電導体を形成し、半導体（ＳＥ）／超電導体（ＳＣ）
接合により設けられる固有の表面ポテンシャルにより決
められたバリア（φB）が形成される（Phys.Rev７１
（１９４７）７１７．Jhon Bardeen）。By the way, a semiconductor (SE) / superconductor (SC) is formed by forming a superconductor on a semiconductor.
A barrier (φ B ) determined by the intrinsic surface potential provided by the junction is formed (Phys.Rev71
(1947) 717. Jhon Bardeen).
【０００５】図３（ａ）は半導体のエネルギバンド図、
図３（ｂ）は超電導体のエネルギバンド図、図３（ｃ）
は半導体／超電導体接合のエネルギバンド図である。こ
れら図において、Ｖは真空準位、Ｅcは伝導体の底、Ｅv
は価電子体のトップ、ＥFはフェルミ準位、ＸSCは超電
導体の仕事関数、ＸSEは半導体の仕事関数、２Δは超電
導エネルギーギャップ（但し、超電導状態臨界温度Ｔｃ
以上では２Δ＝０）である。FIG. 3A is an energy band diagram of a semiconductor,
FIG. 3B is an energy band diagram of the superconductor, and FIG.
FIG. 3 is an energy band diagram of a semiconductor / superconductor junction. In these figures, V is the vacuum level, E c is the bottom of the conductor, and E v
Is the top of the valence body, E F is the Fermi level, X SC is the work function of the superconductor, X SE is the work function of the semiconductor, 2Δ is the superconducting energy gap (however, the superconducting state critical temperature Tc
In the above, 2Δ = 0).
【０００６】一般には、半導体の仕事関数（ＸSE）と超
電導体の仕事関数（ＸSC）の差、即ち、ＸSC−ＸSEがバ
リアφBに相当する。このバリアがショットキーバリア
と呼ばれる。図３（ｃ）に示すように、半導体上に超電
導体を形成すると、φBのバリアが形成され、この接合
の非対称性のため、接合の電流−電圧特性は整流作用を
有する。この整流作用を利用したデバイスは、ショット
キーダイオードと呼ばれ、ＴＴＬロジックやマイクロ波
ミキサー、或いは超電導ベーストランジスタのベース／
コレクタ接合として用いられている。また、高エネルギ
ー型超電導ベーストランジスタでは、この接合がエミッ
タ／ベース接合として用いられている（T.Kobayashi et
al :Jpn. Appl. Phys.25 (1986) p.p.402 参照）。Generally, the difference between the work function (X SE ) of the semiconductor and the work function (X SC ) of the superconductor, that is, X SC -X SE corresponds to the barrier φ B. This barrier is called a Schottky barrier. As shown in FIG. 3C, when a superconductor is formed on a semiconductor, a barrier of φ B is formed, and due to the asymmetry of this junction, the current-voltage characteristic of the junction has a rectifying action. A device that uses this rectification function is called a Schottky diode, and is a base / transistor of a TTL logic, a microwave mixer, or a superconducting base transistor.
Used as a collector junction. This junction is used as an emitter / base junction in high-energy superconducting base transistors (T. Kobayashi et.
al: Jpn. Appl. Phys.25 (1986) pp402).
【０００７】ところで、低エネルギー型超電導ベースト
ランジスタの場合、エミッタ／ベース接合が金属／トン
ネル層／超電導層で構成されるため、低いエネルギーの
準粒子が超電導ベースに注入される。このため、高いバ
リア（φB）のベース／コレクタ接合では、準粒子のコ
レクタ領域への透過率が妨げられるという問題点が有っ
た。By the way, in the case of a low energy type superconducting base transistor, since the emitter / base junction is composed of a metal / tunnel layer / superconducting layer, low energy quasi-particles are injected into the superconducting base. Therefore, in the high barrier (φ B ) base / collector junction, there is a problem that the transmittance of the quasi-particles to the collector region is hindered.
【０００８】この発明は、上述した従来の問題点を解消
するためになされたものにして、半導体／超電導体の接
合バリアを低くして、準粒子の透過率を向上させること
をその目的とする。The present invention has been made to solve the above-mentioned conventional problems, and its object is to lower the junction barrier of semiconductor / superconductor and improve the transmittance of quasi-particles. .
【０００９】[0009]
【課題を解決するための手段】この発明の超電導デバイ
スは、半導体基板上にアルカリ金属、アルカリ土類金
属、又はランタン金属からなる金属層を介して超電導体
層を形成したことを特徴とする。The superconducting device of the present invention is characterized in that a superconducting layer is formed on a semiconductor substrate through a metal layer made of an alkali metal, an alkaline earth metal or a lanthanum metal.
【００１０】[0010]
【作用】アルカリ金属、アルカリ土類金属、又はランタ
ン金属の仕事関数は通常金属の仕事関数に比べ相当低
い。これら金属を半導体上に数Mono Layer（Ｍ・Ｌ）程
度形成すると、半導体上の仕事関数を低くすることが出
来る。従って、この上に超電導体との接合を形成すると
バリア（φB）の高さを低くすることが可能となる。The work function of alkali metal, alkaline earth metal, or lanthanum metal is considerably lower than that of ordinary metal. If these metals are formed on the semiconductor in the order of several Mono Layers (ML), the work function on the semiconductor can be lowered. Therefore, if a junction with a superconductor is formed on this, the height of the barrier (φ B ) can be reduced.
【００１１】[0011]
【実施例】以下、この発明の実施例につき図面を参照し
て説明する。Embodiments of the present invention will be described below with reference to the drawings.
【００１２】アルカリ金属、アルカリ土類金属、又はラ
ンタン金属の仕事関数は、例えば、Ｃｓ：２．１４ｅ
Ｖ，Ｃａ：２．８７ｅＶ，Ｂａ：２．１４ｅＶである。
これに対し、通常金属の仕事関数は、例えば、Ｐｔ：
５．６ｅＶ，Ａｕ：５．１ｅＶ，Ｈｇ：４．５ｅＶ，Ｔ
ｉ：４．３ｅＶである。このように、アルカリ金属、ア
ルカリ土類金属、又はランタン金属の仕事関数は通常金
属の仕事関数に比べ相当低い。The work function of alkali metal, alkaline earth metal, or lanthanum metal is, for example, Cs: 2.14e.
V, Ca: 2.87 eV and Ba: 2.14 eV.
On the other hand, the work function of a normal metal is, for example, Pt:
5.6 eV, Au: 5.1 eV, Hg: 4.5 eV, T
i: 4.3 eV. As described above, the work function of alkali metal, alkaline earth metal, or lanthanum metal is considerably lower than that of ordinary metal.
【００１３】一方、アルカリ金属、アルカリ土類金属、
又はランタン金属は通常活性なので、ショットキー接合
としての材料にされることはないが、これらを超高真空
中、低温で形成することによって、ショットキー接合の
材料として用いることができる。On the other hand, alkali metals, alkaline earth metals,
Or, since lanthanum metal is usually active, it is not used as a material for a Schottky junction, but it can be used as a material for a Schottky junction by forming them in an ultrahigh vacuum at a low temperature.
【００１４】そこで、図１に示すように、半導体として
シリコン（Ｓｉ）１を用い、アルカリ金属としてナトリ
ウム（Ｎａ）を用いて、Ｓｉ上にＮａ層２を０〜１Ｍ・
Ｌ積層することにより、Ｎａ／Ｓｉ接合を形成し、Ｓｉ
上の仕事関数を測定した結果を図４に示す。Therefore, as shown in FIG. 1, silicon (Si) 1 is used as a semiconductor, sodium (Na) is used as an alkali metal, and a Na layer 2 of 0 to 1 M.multidot.
By laminating L, a Na / Si junction is formed,
The result of measuring the above work function is shown in FIG.
【００１５】このＮａ／Ｓｉ接合は、〜５×１０-11Ｔ
ｏｒｒの超高真空中で劈開された７×７パターンがＲＨ
ＥＥＤで観測されるＳｉ基板１上にＭＢＥ法によってＮ
ａ金属を照射することにより形成する。そして、Ｋ−ｃ
ｅｌｌの温度を７２０℃にして照射すると、１０分で１
Ｍ・ＬのＮａ層２を形成することが出来る。図４はその
際約０．１Ｍ・ＬごとにＮａが形成されたときの仕事関
数（Ｗ．Ｆ）を測定したものである。This Na / Si junction is ~ 5 × 10 -11 T
7 × 7 pattern cleaved in ultra high vacuum of orr is RH
N on the Si substrate 1 observed by EED by the MBE method.
a It is formed by irradiating metal. And K-c
When the temperature of the cell is set to 720 ° C and irradiation is performed, it takes 1 minute in 10 minutes.
The ML Na layer 2 can be formed. FIG. 4 shows the measured work function (WF) when Na is formed every about 0.1 M · L.
【００１６】この図から判るように、０．２Ｍ・Ｌ迄に
約２ｅＶの仕事関数の減少が見られ、０．５Ｍ・Ｌ以上
積層してもあまり減少が見られない。このことより、約
１Ｍ・Ｌの低仕事関数金属を半導体上に積層した接合に
は、バリア（φB）としては負の値のものを形成するこ
とが出来る。このことを利用して、低いバリアの半導体
と超電導体との接合を形成することが出来る。即ち、図
２に示すように、半導体１上にアルカリ金属、アルカリ
土類金属、又はランタン金属の低仕事関数の金属層２を
介して超電導体層３を形成すれば良い。As can be seen from this figure, the work function decreases by about 2 eV by 0.2 M · L, and does not decrease much by stacking more than 0.5 M · L. As a result, a barrier (φ B ) having a negative value can be formed in a junction in which a low work function metal of about 1 M · L is laminated on a semiconductor. Utilizing this, a junction between a semiconductor having a low barrier and a superconductor can be formed. That is, as shown in FIG. 2, the superconductor layer 3 may be formed on the semiconductor 1 through the low work function metal layer 2 of alkali metal, alkaline earth metal, or lanthanum metal.
【００１７】しかし、これら低仕事関数の金属はイオン
になりやすく一般に固体内に拡散しやすい。例えば、超
電導体としてＮｂを用いて、図２に示すように半導体
（Ｓｉ）／アルカリ金属（Ｎａ）（１Ｍ・Ｌ）／超電導
体（Ｎｂ）の接合を作る場合、通常４００℃の基板温度
でイオンビーム蒸着によりＮｂを積層形成するが、この
温度では、ＮａはＳｉとＮｂの両方に拡散されてしま
い、Ｎｂ／Ｓｉの接合が形成され、低いバリアの半導体
と超電導体との接合を形成することは出来ない。However, these low work function metals easily become ions and generally diffuse into solids. For example, when Nb is used as a superconductor and a semiconductor (Si) / alkali metal (Na) (1M · L) / superconductor (Nb) junction is made as shown in FIG. 2, a substrate temperature of 400 ° C. is usually used. Nb is laminated by ion beam vapor deposition, but at this temperature, Na is diffused into both Si and Nb, and a Nb / Si junction is formed to form a low barrier semiconductor-superconductor junction. I can't do that.
【００１８】そこで、この拡散を防ぐために、例えば、
半導体（Ｓｉ）／アルカリ金属（Ｎａ）（１Ｍ・Ｌ）／
超電導体（Ｎｂ）の接合を作る場合、Ｎｂ形成時の基板
温度を０℃〜１５０℃の温度に限定し、１×１０-10Ｔ
ｏｒｒのＭＢＥ装置内で１Å／秒のＥＢレートで１００
０秒形成することにより、バリアのない、即ち整流作用
の小さい接合を得ることが出来た。Therefore, in order to prevent this diffusion, for example,
Semiconductor (Si) / Alkali metal (Na) (1M ・ L) /
When making a superconductor (Nb) joint, the substrate temperature during Nb formation is limited to a temperature of 0 ° C to 150 ° C, and 1 x 10 -10 T
100 at EB rate of 1Å / sec in the MBE device of orr
By forming it for 0 second, it was possible to obtain a junction having no barrier, that is, a small rectifying effect.
【００１９】上記低仕事関数の金属としては、Ｎａ以外
にアルカリ金属としてＫ，Ｒｂ，Ｃｓ又、アルカリ土類
金属として、Ｍｇ，Ｃａ，Ｂａ更にランタン系金属とし
てＬａ，Ｐｒ，Ｎｄ，Ｓｍを用いることが出来る。これ
ら各金属を半導体上に１Ｍ・Ｌ形成する条件を表１に示
す。In addition to Na, K, Rb, Cs as an alkali metal, Mg, Ca, Ba as an alkaline earth metal, and La, Pr, Nd, Sm as a lanthanum-based metal are used as the above-mentioned low work function metal. You can Table 1 shows the conditions for forming each of these metals on the semiconductor by 1 M · L.
【００２０】[0020]
【表１】 [Table 1]
【００２１】又、これら低仕事関数金属の上に積層する
金属系超電導体とその形成条件を表２に示す。Table 2 shows metal superconductors laminated on these low work function metals and their forming conditions.
【００２２】[0022]
【表２】 [Table 2]
【００２３】次に、この発明を酸化物超電体を用いた低
エネルギー型超電導ベーストランジスタに適用した実施
例につき図５を参照して説明する。Next, an embodiment in which the present invention is applied to a low energy type superconducting base transistor using an oxide superconductor will be described with reference to FIG.
【００２４】この実施例においては、酸化物超電導体と
しては、ＢＫＢＯを用いた。先ずＮｂを０．０５〜０．
５重量％ドープしたＳｒＴｉＯ3単結晶基板５を用意す
る。そして、このＳｒＴｉＯ3単結晶基板５をトリクレ
ン、アセトン、メタノールを使って洗浄する。洗浄はト
リクレン中に超音波１０分間、アセトン中に超音波１０
分間、メタノール中に超音波１０分間漬けそれぞれ行
う。その洗浄が終わった後、真空オーブン１２０℃中で
１０分間乾燥させた後、ＭＢＥ装置の真空チャンバー内
にセットする。このチャンバー内を１×１０-10Ｔｏｒ
ｒの超高真空に設定した後、ＳｒＴｉＯ3単結晶基板５
を７２０℃の温度による熱クリーニングを５分間施す。In this example, BKBO was used as the oxide superconductor. First, Nb is set to 0.05 to 0.
A SrTiO 3 single crystal substrate 5 doped with 5 wt% is prepared. Then, the SrTiO 3 single crystal substrate 5 is washed with trichlene, acetone and methanol. Wash with ultrasonic waves for 10 minutes in trichlene and ultrasonic waves in acetone for 10 minutes.
And sonicate in methanol for 10 minutes. After the cleaning is completed, the product is dried in a vacuum oven at 120 ° C. for 10 minutes and then set in the vacuum chamber of the MBE apparatus. 1 × 10 -10 Tor in this chamber
SrTiO 3 single crystal substrate 5 after setting to ultra high vacuum of r
Is subjected to heat cleaning at a temperature of 720 ° C. for 5 minutes.
【００２５】そして、基板温度を３００℃に設定し、Ｓ
ｒＴｉＯ3単結晶基板５上にアルカリ金属のＫ又はＲｂ
を１〜１０Ｍ・Ｌ形成して、アルカリ金属膜６を設け
る。Then, the substrate temperature is set to 300 ° C. and S
Alkali metal K or Rb on the rTiO 3 single crystal substrate 5
1 to 10 M · L and the alkali metal film 6 is provided.
【００２６】このアルカリ金属膜６の形成時に、Ｂａ，
Ｂｉのセルも加熱しておく。Ｋ又はＲｂのアルカリ金属
膜６が所定の１〜１０Ｍ・Ｌ形成された後、Ｂａのフラ
ックス射出を始め、そしてＯ2プラズマを導入する。そ
の後全セルを開いてＢＫＢＯ膜７をアルカリ金属膜６の
上に１０００Å積層形成する。When the alkali metal film 6 is formed, Ba,
The cell of Bi is also heated. After the K or Rb alkali metal film 6 is formed in a predetermined amount of 1 to 10 M · L, Ba flux injection is started, and O 2 plasma is introduced. After that, all the cells are opened and the BKBO film 7 is formed on the alkali metal film 6 by 1000 Å lamination.
【００２７】ＢＫＢＯ膜７の形成後後、乾燥大気にさら
すことにより、ＢＫＢＯ膜３上に自然バリア８が形成さ
れる。この自然バリア４を絶縁膜として用いる。After forming the BKBO film 7, the natural barrier 8 is formed on the BKBO film 3 by exposing to the dry atmosphere. This natural barrier 4 is used as an insulating film.
【００２８】次に、ＢＫＢＯ薄膜７が形成された基板５
を電子ビーム蒸着装置の真空チャンバー内に入れ、Ａｕ
からなる膜厚１０００Åのエミッタ領域９を電子ビーム
蒸着により自然バリア８上に形成して、ベース／コレク
タのバリア（φB）がほどんどない接合が形成された低
エネルギー型超電導ベーストランジスタを得ることが出
来る。Next, the substrate 5 on which the BKBO thin film 7 is formed
Into the vacuum chamber of the electron beam evaporation system, and
To form a low energy superconducting base transistor in which an emitter region 9 having a film thickness of 1000 Å is formed on a natural barrier 8 by electron beam evaporation to form a junction having a bare base / collector barrier (φ B ). Can be done.
【００２９】[0029]
【発明の効果】以上説明したように、この発明によれ
ば、半導体上の仕事関数を低くすることができるので、
この上に超電導体との接合を形成するとバリア（φB）
の高さを低くすることが可能となり、準粒子の透過率を
向上させることができる。As described above, according to the present invention, since the work function on the semiconductor can be lowered,
When a junction with a superconductor is formed on this, a barrier (φ B )
It is possible to lower the height of the particles and improve the transmittance of the quasi-particles.
【図１】この発明の一実施例を示す断面図である。FIG. 1 is a sectional view showing an embodiment of the present invention.
【図２】この発明の一実施例を示す断面図である。FIG. 2 is a sectional view showing an embodiment of the present invention.
【図３】図３（ａ）は半導体のエネルギバンド図、図３
（ｂ）は超電導体のエネルギバンド図、図３（ｃ）は半
導体／超電導体接合のエネルギバンド図である。3 (a) is an energy band diagram of a semiconductor, FIG.
FIG. 3B is an energy band diagram of a superconductor, and FIG. 3C is an energy band diagram of a semiconductor / superconductor junction.
【図４】Ｎａ金属層との膜厚とシリコン上の仕事関数と
の関係を示す図である。FIG. 4 is a diagram showing a relationship between a film thickness with a Na metal layer and a work function on silicon.
【図５】この発明を酸化物超電体を用いた低エネルギー
型超電導ベーストランジスタに適用した実施例を示す断
面図である。FIG. 5 is a sectional view showing an embodiment in which the present invention is applied to a low energy type superconducting base transistor using an oxide superconductor.
【図６】従来の低エネルギー型超電導ベーストランジス
タを示す断面図である。FIG. 6 is a cross-sectional view showing a conventional low energy superconducting base transistor.
１ 半導体 ２ 低仕事関数の金属層（Ｎａ） ３ 超電導体層 1 Semiconductor 2 Low Work Function Metal Layer (Na) 3 Superconductor Layer
───────────────────────────────────────────────────── フロントページの続き (72)発明者 善里 順信 大阪府守口市京阪本通２丁目18番地 三洋 電機株式会社内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junnobu Zenzato 2-18, Keihanhondori, Moriguchi City, Osaka Prefecture Sanyo Electric Co., Ltd.
Claims (1)
土類金属、又はランタン金属からなる金属層を介して超
電導体層を形成してなる超電導デバイス。1. A superconducting device in which a superconductor layer is formed on a semiconductor substrate with a metal layer made of an alkali metal, an alkaline earth metal or a lanthanum metal interposed therebetween.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP04333585A JP3124641B2 (en) | 1992-11-18 | 1992-11-18 | Superconducting device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP04333585A JP3124641B2 (en) | 1992-11-18 | 1992-11-18 | Superconducting device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06164004A true JPH06164004A (en) | 1994-06-10 |
| JP3124641B2 JP3124641B2 (en) | 2001-01-15 |
Family
ID=18267694
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP04333585A Expired - Fee Related JP3124641B2 (en) | 1992-11-18 | 1992-11-18 | Superconducting device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3124641B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6720654B2 (en) * | 1998-08-20 | 2004-04-13 | The United States Of America As Represented By The Secretary Of The Navy | Electronic devices with cesium barrier film and process for making same |
| US6734558B2 (en) * | 1998-08-20 | 2004-05-11 | The United States Of America As Represented By The Secretary Of The Navy | Electronic devices with barium barrier film and process for making same |
| US6881669B2 (en) | 2000-05-03 | 2005-04-19 | The United States Of America As Represented By The Secretary Of The Navy | Process for making electronic devices having a monolayer diffusion barrier |
-
1992
- 1992-11-18 JP JP04333585A patent/JP3124641B2/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6720654B2 (en) * | 1998-08-20 | 2004-04-13 | The United States Of America As Represented By The Secretary Of The Navy | Electronic devices with cesium barrier film and process for making same |
| US6734558B2 (en) * | 1998-08-20 | 2004-05-11 | The United States Of America As Represented By The Secretary Of The Navy | Electronic devices with barium barrier film and process for making same |
| US6881669B2 (en) | 2000-05-03 | 2005-04-19 | The United States Of America As Represented By The Secretary Of The Navy | Process for making electronic devices having a monolayer diffusion barrier |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3124641B2 (en) | 2001-01-15 |
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