CN103531648A - InGaAs heterojunction infrared detector line array and preparing method thereof - Google Patents

Abstract

The invention provides an InGaAs nano-heterojunction infrared detector line array and a preparation method thereof. First, an upper electrode is prepared on a substrate, and an amorphous gallium arsenide buffer layer, a gallium arsenide nanocrystal layer, and an indium gallium arsenide layer are sequentially grown. Nanocrystalline layer, and then prepare the lower electrode to form an InGaAs nano-heterojunction infrared detector line array. The infrared photosensitive layer of the present invention is a nanocrystalline material, which is simple to prepare, and can prepare an InGaAs film with a high In composition to expand the detection range , and is an uncooled infrared detector, works at room temperature, has small volume, light weight and low cost.

Description

A line array of InGaAs nano-heterojunction infrared detectors and its preparation method

technical field

The invention belongs to the field of infrared detector materials and devices, and in particular relates to the preparation of infrared detector line arrays with nano-heterojunction structures by using III-V nanocrystalline materials and a preparation method thereof.

Background technique

InGaAs (indium gallium arsenide) ternary compound semiconductor (matched to InP substrate) has been proved to be a short-wave infrared detector material (0.9~1.7μm), and its room temperature detection is ~10 ¹³ cmHz ^1/2 W. Compared with Ge detectors working in this spectral region, this detector has lower dark current and noise; increasing the proportion of In components can extend the detector cut-off wavelength to 2.6 μm; the detection range can be 1-2.4 μm . The detector made of this material does not need refrigeration, so it is an uncooled infrared detector, which can meet the needs of the civilian market for low power consumption, small size, light weight, high cost performance, and easy use. Therefore, InGaAs Short-wave infrared detection devices made of materials have received more attention and research. In recent years, in the fields of space imaging (including earth remote sensing, atmospheric detection, and environmental monitoring, etc.) and spectroscopy, the demand for high In composition In _x Ga _1-x As detection devices has been increasing, especially with a cut-off wavelength of 2.5 μm ( Corresponding to the In _0.82 Ga _0.18 As infrared detection device whose In composition is 0.82).

InGaAs materials have many advantages in optoelectronic devices in the near-infrared band of 1~3μm, and phased research results have been achieved, and some InGaAs detector line arrays have been obtained, but the performance and volume of unit devices restrict large-area infrared devices. The development of focal plane array detectors still has a certain distance from practicality. To obtain a large-area infrared detector array, it is necessary to solve the uniformity of large-area materials and the uniformity of unit device performance. At the same time, it is necessary to reduce the volume and weight of unit devices, simplify the structure, and reduce costs.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art, to provide a kind of InGaAs nano-heterojunction infrared detector line array and its preparation method, the infrared detector line array prepared by this method has the uniformity of large-area materials, Its unit device is small in size, light in weight and low in cost.

The object of the present invention is achieved like this: this infrared detector line array is made up of the unit device of a plurality of linear arrangements, and described unit device comprises substrate, the band-shaped Au film lower electrode prepared on the substrate, the lower electrode An amorphous GaAs buffer layer, a GaAs nanocrystalline layer and an InGaAs nanocrystalline layer grown sequentially on the top, and an annular Au film upper electrode prepared on the InGaAs nanocrystalline layer. The amorphous GaAs buffer layer, the GaAs nanocrystalline layer and the InGaAs nanocrystalline layer constitute a nano-heterojunction, which uses the interface potential of different semiconductors to build an electric field in the heterojunction to realize the driving effect on the photoinduced charge component.

The preparation method of the InGaAs nano-heterojunction infrared detector line array comprises the following steps:

①. First, photolithographically engrave the lower electrode image on the glass substrate, use photoresist as a mask, and use magnetron sputtering technology to prepare the lower electrode Au film, remove the photoresist and the Au film on it, and form a strip-shaped lower electrode ;

②. Photoetching the circular pattern of the infrared photosensitive layer, using photoresist as a mask to grow the photosensitive layer;

③. Use metal-organic vapor deposition technology to first grow an amorphous GaAs buffer layer on the lower electrode, the growth temperature is 500°C, and the V/III ratio (the ratio of the sum of the molar flow of the V-group source flowing into the reaction chamber to the sum of the molar flow of the III-group source ) is 40, and the film thickness is 10nm;

④. Using metal-organic vapor deposition technology to grow GaAs nanocrystalline layer on the buffer layer, the growth temperature is 500°C, the V/III ratio is 60, the total carrier gas flow rate is 8L/min, and the film thickness is 30-40nm. The average size is 3-4nm;

⑤. Using metal-organic vapor deposition technology to grow InGaAs nanocrystalline layer on GaAs nanocrystalline layer, the growth temperature is 500°C, the V/III ratio is 60, the total carrier gas flow rate is 8L/min, and the film thickness is 60-70nm. Nanocrystalline The average particle size is 3-4nm, the molar flow rate of the TMG (trimethylgallium) source is fixed, and the InGaAs film with different In components is grown by changing the molar flow rate of the TMIn (trimethylindium) source;

6. Remove the photoresist and the buffer layer, GaAs nanocrystalline layer and InGaAs nanocrystalline layer 5 on the photoresist, photoengrav the upper electrode image, use the photoresist as a mask, and utilize the magnetron sputtering technology to form the Au film of the upper electrode, Remove the photoresist and the Au film on it to form a ring-shaped upper electrode.

The present invention grows the InGaAs infrared column detector of nano-heterojunction on a substrate, which has the following advantages:

(1) The infrared photosensitive layer of the infrared detector line array of the present invention is a nanocrystalline material, which is easy to prepare, and an InGaAs film with a high In composition can be prepared to expand the detection range;

(2) The infrared detector line array of the present invention is an uncooled infrared detector, which works at room temperature;

(3) The unit device of the infrared detector line array of the present invention is small in size, light in weight and low in cost;

(4) The infrared detector line array of the present invention is a line structure, which is beneficial to the improvement of the detection degree.

Description of drawings

Figure 1 is a schematic diagram of the unit device structure of the InGaAs nano-heterojunction infrared detector line array.

Fig. 2 is a schematic structural diagram of an InGaAs nano-heterojunction infrared detector line array with six unit devices.

Detailed ways

Specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

As shown in Figure 2, the infrared detector line array is composed of six linearly arranged unit devices, including the lower electrode 2 prepared on the substrate 1, the photosensitive layers 3, 4, 5 grown on the lower electrode 2, and the upper Electrode 6. The cross-sectional structure of each unit device is shown in Figure 1, which includes a substrate 1, a strip-shaped lower electrode 2 prepared on the substrate 1, an amorphous GaAs buffer layer 3 grown sequentially on the lower electrode 2, GaAs nanometer crystalline layer 4 and InGaAs nanocrystalline layer 5, on which an annular upper electrode 6 is prepared.

The amorphous GaAs buffer layer 3 , the GaAs nano-crystal layer 4 and the InGaAs nano-crystal layer 5 constitute an InGaAs nano-heterojunction infrared photosensitive layer.

The preparation method comprises the following steps:

1) Firstly, photolithographically engrave the strip-shaped image of the lower electrode on the glass substrate 1, using positive photoresist, the photosensitive pattern is strip-shaped, and dissolving the photosensitive photoresist in the developer solution, and the photoresist outside the strip-shaped area It cannot be dissolved in the developer solution, and is left on the substrate as a mask, and then the Au film is sputtered by magnetron sputtering technology, and the photoresist and the Au film on it are removed to form a strip-shaped lower electrode 2;

2) The circular pattern of the infrared photosensitive layer is photoetched using positive photoresist, the photosensitive pattern is circular, and the photosensitive photoresist is dissolved in the developer, and the photoresist outside the circular area cannot be dissolved in the developer , stay on the substrate as a mask to grow the photosensitive layer;

3) First grow an amorphous GaAs buffer layer 3 on the lower electrode 2 by using metal-organic vapor deposition technology, the growth temperature is 500°C, and the V/III ratio (the sum of the molar flow rates of the V-group sources flowing into the reaction chamber and the molar flow rate of the III-group sources and the ratio) is 40, and the film thickness is 10nm;

4) GaAs nanocrystalline layer 4 was grown on the buffer layer 3 by metal-organic vapor deposition technology, the growth temperature was 500°C, the V/III ratio was 60, the total carrier gas flow rate was 8L/min, and the film thickness was 40nm. The average size is 3-4 nm;

5) The InGaAs nanocrystalline layer was grown on the GaAs nanocrystalline layer 4 by metal-organic vapor deposition technology, the growth temperature was 500°C, the V/III ratio was 60, the total carrier gas flow rate was 8L/min, and the film thickness was 70nm. The average particle size is 3-4nm, the molar flow rate of the TMG source is fixed, and the InGaAs film with different In components is grown by changing the molar flow rate of the TMIn source;

6), removing the photoresist used as a mask and the buffer layer 3, GaAs nanocrystalline layer 4 and InGaAs nanocrystalline layer 5 on it to form a circular infrared photosensitive layer;

7) Photoresist the upper electrode image, using positive photoresist, the photosensitive pattern is circular, and the photosensitive photoresist is dissolved in the developer solution. Make a mask on the substrate, and then use the magnetron sputtering technology to sputter the Au film, remove the photoresist and the Au film on it, and form the annular upper electrode 6.

The structure of the InGaAs nano-heterojunction infrared detector line array is shown in FIG. 2 . The substrate 1 can be selected from glass, silicon and sapphire substrates; the lower electrode 2 is strip-shaped; the photosensitive layer of the infrared detector is a circular structure, including a GaAs nanocrystalline layer 4 and an InGaAs nanocrystalline layer 5 grown on the buffer layer 3 to form Nano-heterojunction; the lower electrode 6 is circular.

The diameter of the circular infrared photosensitive layer is larger than the width of the Au band of the lower electrode 6, so that the upper electrode 2 covers the substrate 1 without short circuit.

Implementation Effect:

The detection rate of the InGaAs nano-heterojunction infrared detector line array was tested. During the test, the temperature of the blackbody is kept at 1000K, the modulation frequency of the blackbody is 1000Hz, the radiation power of the blackbody is 617.95μW/cm ² , the bias current is 0.02mA, the test temperature is 300K, and the detection rate can reach the order of 10 ⁹ cmHz ^1/2 W ^-1 .

Claims (8)

1. an InGaAs nano heterojunction Infrared Detectors linear array, it is characterized in that: this Infrared Detectors linear array is comprised of the unit component of a plurality of linear array, described unit component comprises substrate (1), banded Au film bottom electrode (2) in the upper preparation of substrate (1), amorphous GaAs resilient coating (3), GaAs nanometer crystal layer (4) and the InGaAs nanometer crystal layer (5) of on bottom electrode (2), growing successively, and at the upper circular Au film top electrode (6) of preparing of InGaAs nanometer crystal layer (5).

2. a kind of InGaAs nano heterojunction Infrared Detectors linear array according to claim 1, is characterized in that: described substrate is sapphire, glass or silicon substrate.

3. a kind of InGaAs nano heterojunction Infrared Detectors linear array according to claim 1, it is characterized in that: described bottom electrode (2) is for banded, power on level (6) circlewise, and the part in ring is the infrared photosensitive layer of InGaAs nano heterojunction consisting of amorphous GaAs resilient coating (3), GaAs nanometer crystal layer (4) and InGaAs nanometer crystal layer (5).

4. a kind of InGaAs nano heterojunction Infrared Detectors linear array according to claim 1, is characterized in that: the thick 10nm of described amorphous GaAs resilient coating (3), the thick 30-40nm of GaAs nanometer crystal layer (4), the thick 60-70nm of InGaAs nanometer crystal layer (5).

5. a kind of InGaAs nano heterojunction Infrared Detectors linear array according to claim 1, is characterized in that:

Described nanocrystal average-size is at 3-4nm.

6. a preparation method for InGaAs nano heterojunction Infrared Detectors linear array, is characterized in that:

The method comprises the following steps:

1., first at substrate (1) glazing, inscribe electrode image, shelter with photoresist, utilize magnetron sputtering technique to make bottom electrode Au film, remove photoresist and on Au film, form banded bottom electrode (2);

2., the circular pattern of the infrared photosensitive layer of photoetching, utilize photoresist to shelter growth photosensitive layer;

3., utilize first the grow resilient coating (3) of amorphous GaAs of metal organic chemical vapor deposition technology on bottom electrode (2), 500 ℃ of growth temperatures, V/III ratio is 40, thickness is 10nm;

4., utilize metal organic chemical vapor deposition technology at the upper growth of resilient coating (3) GaAs nanometer crystal layer (4), 500 ℃ of growth temperatures, V/III ratio is 60, total carrier gas flux is 8L/min, thickness is 40nm;

5., utilize metal organic chemical vapor deposition technology at the upper growth of GaAs nanometer crystal layer (4) InGaAs nanometer crystal layer (5), 500 ℃ of growth temperatures, V/III ratio is 60, total carrier gas flux is 8L/min, thickness is 70nm, the fixing molar flow in TMG source, by changing the InGaAs film of the molar flow growth different I n component in TMIn source;

6., remove photoresist and on resilient coating, GaAs nanometer crystal layer and InGaAs nanometer crystal layer, photoetching top electrode image, shelters with photoresist, adopts magnetron sputtering technique to prepare top electrode Au film, remove photoresist and on Au film, form circular top electrode (6).

7. a kind of InGaAs nano heterojunction Infrared Detectors linear array according to claim 1, it is characterized in that: in order to prevent short circuit, the width of banded Au film bottom electrode (2) is less than circular infrared photosensitive layer diameter, is unlikely to short circuit so that bottom electrode (2) covers on substrate 1.

A kind of InGaAs nano heterojunction Infrared Detectors linear array according to claim 2 preparation method, it is characterized in that: described V/III flows into the group V source molar flow sum of reative cell and the ratio of III clan source molar flow sum than referring to.

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