阅读说明：本技术 双色红外探测器及其制作方法 (Double-color infrared detector and manufacturing method thereof ) 是由 黄勇 赵宇 吴启花 熊敏 于 2019-04-09 设计创作，主要内容包括：本发明公开了一种双色红外探测器,包括n型衬底以及依序层叠设置于所述n型衬底上的第一n型接触层、n型蓝色通道层、p型连接层、n型红色通道层和第二n型接触层,所述第一n型接触层上还设有第一电极,所述第二n型接触层上设有与所述第一电极对应的第二电极。本发明还公开了上述双色红外探测器的制作方法。本发明解决了在双色红外探测器中,当一个通道工作时另一个通道产生的少子容易扩散至工作的通道上,从而产生较大的串音的问题。(The invention discloses a bicolor infrared detector which comprises an n-type substrate, and a first n-type contact layer, an n-type blue channel layer, a p-type connecting layer, an n-type red channel layer and a second n-type contact layer which are sequentially stacked on the n-type substrate, wherein a first electrode is further arranged on the first n-type contact layer, and a second electrode corresponding to the first electrode is arranged on the second n-type contact layer. The invention also discloses a manufacturing method of the double-color infrared detector. The invention solves the problem that in a double-color infrared detector, when one channel works, minority carriers generated by the other channel are easy to diffuse to the working channel, thereby generating larger crosstalk.)

1. The bicolor infrared detector is characterized by comprising an n-type substrate (1), and a first n-type contact layer (2), an n-type blue channel layer (3), a p-type connecting layer (4), an n-type red channel layer (5) and a second n-type contact layer (6) which are sequentially stacked on the n-type substrate (1), wherein a first electrode (7) is further arranged on the first n-type contact layer (2), and a second electrode (8) corresponding to the first electrode (7) is arranged on the second n-type contact layer (6).

2. The dual-color infrared detector according to claim 1, wherein the n-type blue channel layer (3) comprises an n-type blue channel absorption layer (31) and an n-type blue channel barrier layer (32) which are sequentially stacked and disposed on the first n-type contact layer (2);

the n-type red channel layer (5) comprises an n-type red channel barrier layer (51) and an n-type red channel absorption layer (52) which are sequentially stacked and arranged on the p-type connecting layer (4).

3. The dual color infrared detector according to claim 2, characterized in that the valence bands of the n-type blue channel absorption layer (31), the n-type blue channel barrier layer (32), the n-type red channel barrier layer (51), the n-type red channel absorption layer (52) and the p-type connection layer (4) are mutually flush.

4. The dual color infrared detector according to claim 3, characterized in that the effective bandwidths of the p-type connection layer (4), the n-type blue channel barrier layer (32) and the n-type blue channel absorption layer (31) decrease in order; the effective bandwidths of the p-type connection layer (4), the n-type red channel barrier layer (51), and the n-type red channel absorber layer (52) decrease in order.

5. The dual color infrared detector of claim 3, wherein the effective bandwidth of the n-type blue channel absorbing layer (31) is greater than the effective bandwidth of the n-type red channel absorbing layer (52).

6. The dual color infrared detector according to any of claims 2 to 5, characterized in that the first n-type contact layer (2), the n-type blue channel absorption layer (31), the n-type blue channel barrier layer (32), the n-type red channel barrier layer (51), the n-type red channel absorption layer (52) and the second n-type contact layer (6) are Si-doped n-type InAs/GaSb superlattices and/or n-type InAs/InAsSb superlattices, and the p-type connection layer (4) is a Zn-or Be-doped p-type InAs/GaSb superlattice or a p-type InAs/InAsSb superlattice.

7. The dual color infrared detector according to claim 6, characterized in that the n-type substrate (1) is n-type GaSb or InAs.

8. A manufacturing method of a bicolor infrared detector is characterized by comprising the following steps:

sequentially laminating a first n-type contact layer (2), an n-type blue channel absorption layer (31), an n-type blue channel barrier layer (32), a p-type connection layer (4), an n-type red channel barrier layer (51), an n-type red channel absorption layer (52) and a second n-type contact layer (6) on an n-type substrate (1);

locally etching the second n-type contact layer (6), the n-type red channel absorption layer (52), the n-type red channel barrier layer (51), the p-type connection layer (4), the n-type blue channel barrier layer (32) and the n-type blue channel absorption layer (31) to expose the first n-type contact layer (2) to form a detector mesa structure (A);

a first electrode (7) is formed on the first n-type contact layer (2), and a second electrode (8) is formed on the second n-type contact layer (6).

9. The method of manufacturing according to claim 8, wherein the valence bands of the n-type blue channel absorption layer (31), the n-type blue channel barrier layer (32), the n-type red channel barrier layer (51), the n-type red channel absorption layer (52), and the p-type connection layer (4) are flush with each other.

10. The fabrication method according to claim 9, wherein the effective bandwidths of the p-type connection layer (4), the n-type blue channel barrier layer (32) and the n-type blue channel absorption layer (31) are sequentially decreased; the effective bandwidths of the p-type connection layer (4), the n-type red channel barrier layer (51) and the n-type red channel absorption layer (52) are sequentially decreased; the effective bandwidth of the n-type blue channel absorbing layer (31) is greater than the effective bandwidth of the n-type red channel absorbing layer (52).

Technical Field

The invention relates to the field of semiconductors, in particular to a bicolor infrared detector and a manufacturing method thereof.

Background

Infrared radiation detection is an important component of infrared technology and is widely applied to the fields of thermal imaging, satellite remote sensing, gas monitoring, optical communication, spectral analysis and the like. The antimonide second-class superlattice (InAs/GaSb or InAs/InAsSb) infrared detector is considered to be one of the most ideal choices for preparing the third-generation infrared detector due to the characteristics of good uniformity, low Auger recombination rate, large wavelength adjusting range and the like. Compared with a mercury cadmium telluride infrared detector (HgCdTe), the mercury cadmium telluride infrared detector has better uniformity repeatability, lower cost and better performance in a long-wavelength and very-long-wavelength band; compared with a quantum well infrared detector (QWIP), the quantum well infrared detector has the advantages of higher quantum efficiency, smaller dark current and simpler process. At present, the antimonide second-class superlattice infrared detectors are already industrialized.

One of the major features of the third generation infrared detection systems is the ability to detect two colors or even multiple colors. The double-color detector can provide information of two infrared bands at the same time, can obtain the absolute temperature of a target, inhibit background interference, increase detection and identification distances, reduce false alarm rate, and remarkably improve the performance of the system and the universality on various weapon platforms. Two-color infrared detectors generally adopt a form that two PN junctions are placed together back to back, each PN junction corresponds to an absorption band, usually, an infrared band with a shorter wavelength is called a blue channel and is placed closer to the incident light direction, and an infrared band with a longer wavelength is called a red channel and is placed behind the blue channel. One band operates at forward bias and the other band operates at reverse bias. The university of northwest in the united states of 2008 proposes a two-color detector (pierce-Yves Delaunay et al, Applied physics letter 92,111112,2008) of antimonide superlattice, and the device is based on two back-to-back homogeneous pin junctions and has the defects of high dark current, large crosstalk and the like. The United states northwest university of 2012 proposed a medium and long wavelength antimonide superlattice two-color detector (Edward Kwei-wei Huang et al, Optics Letter 37,4744,2012, see Zhi Jiang et al, Infred Physics for similar structure&Technology 86,159,2017). As shown in FIG. 1, each band adopts a double heterojunction structure, wherein the absorption region adopts weak p-type doping and p is used^-Is represented as np^-pp^-And n is a structure. In the figure, R denotes a red channel detector, B denotes a blue channel detector, C denotes an infrared light absorption layer of two channels, and a plurality of arrows denote the incident directions of infrared light. Referring to fig. 1, it can be seen that the two PN junctions of the dual-color infrared detector are disposed on the infrared absorption layer CTwo sides, and an infrared light absorption layer C is arranged in the middle of the whole bicolor infrared detector. Since the infrared absorption layers C of the two channels are all p-type materials without the limitation of potential barriers, this structure may cause a problem in that when one channel operates, minority carriers generated from the other channel easily diffuse to the operating channel, thereby generating large crosstalk. Therefore, it is necessary to develop a new antimonide dual-color infrared detector, which adopts a new and simple structure form, increases the potential barrier, inhibits crosstalk, reduces dark current and improves the comprehensive performance of the detector.

Disclosure of Invention

In order to achieve the purpose, the invention adopts the following technical scheme:

a bicolor infrared detector comprises an n-type substrate, and a first n-type contact layer, an n-type blue channel layer, a p-type connecting layer, an n-type red channel layer and a second n-type contact layer which are sequentially stacked on the n-type substrate, wherein a first electrode is further arranged on the first n-type contact layer, and a second electrode corresponding to the first electrode is arranged on the second n-type contact layer.

Preferably, the n-type blue channel layer comprises an n-type blue channel absorption layer and an n-type blue channel barrier layer which are sequentially stacked and arranged on the first n-type contact layer;

the n-type red channel layer comprises an n-type red channel barrier layer and an n-type red channel absorption layer which are sequentially stacked on the p-type connecting layer.

Preferably, the valence bands of the n-type blue channel absorber layer, the n-type blue channel barrier layer, the n-type red channel absorber layer, and the p-type connection layer are flush with each other.

Preferably, the effective bandwidths of the p-type connection layer, the n-type blue channel barrier layer, and the n-type blue channel absorber layer decrease in order; the effective bandwidths of the p-type connection layer, the n-type red channel barrier layer, and the n-type red channel absorber layer decrease in order.

Preferably, the effective bandwidth of the n-type blue channel absorber layer is greater than the effective bandwidth of the n-type red channel absorber layer.

Preferably, the first n-type contact layer, the n-type blue channel absorption layer, the n-type blue channel barrier layer, the n-type red channel absorption layer and the second n-type contact layer are Si-doped n-type InAs/GaSb superlattices and/or n-type InAs/InAsSb superlattices, and the p-type connection layer is a Zn-or Be-doped p-type InAs/GaSb superlattice or a p-type InAs/InAsSb superlattice.

Preferably, the n-type substrate is n-type GaSb or InAs.

The invention also provides a manufacturing method of the double-color infrared detector, which comprises the following steps:

sequentially laminating a first n-type contact layer, an n-type blue channel absorption layer, an n-type blue channel barrier layer, a p-type connection layer, an n-type red channel barrier layer, an n-type red channel absorption layer and a second n-type contact layer on an n-type substrate;

the second n-type contact layer, the n-type red channel absorption layer, the n-type red channel barrier layer, the p-type connection layer, the n-type blue channel barrier layer and the n-type blue channel absorption layer are partially etched, so that the first n-type contact layer is exposed to form a detector mesa structure;

a first electrode is formed on the first n-type contact layer and a second electrode is formed on the second n-type contact layer.

Preferably, the valence bands of the n-type blue channel absorber layer, the n-type blue channel barrier layer, the n-type red channel absorber layer, and the p-type connection layer are flush with each other.

Preferably, the effective bandwidths of the p-type connection layer, the n-type blue channel barrier layer, and the n-type blue channel absorber layer decrease in order; the effective bandwidths of the p-type connecting layer, the n-type red channel barrier layer and the n-type red channel absorption layer are sequentially decreased; the effective bandwidth of the n-type blue channel absorber layer is greater than the effective bandwidth of the n-type red channel absorber layer.

Compared with the prior art, the invention has the beneficial effects that:

(1) the p-type connecting layer is arranged in the middle of the detector, the heterojunction and the absorption region are arranged on two sides of the p-type connecting layer, and the electron barrier comprises a heterojunction barrier and a PN junction barrier, so that the electron barrier is maximized, minority carriers generated by the absorption layer of the device corresponding to one waveband are difficult to cross the barrier when the device of the other waveband works, and the electrical crosstalk is restrained to the maximum extent.

(2) Each wave band (blue channel and red channel) of the double-color detector adopts the n-type absorption layer and the n-type electronic barrier layer, and the n-type absorption layer and the n-type electronic barrier layer and the p-type connecting layer form a single heterojunction structure together, so that dark current can be well inhibited, the transport of photocurrent is ensured by the level of a valence band, and the structure of the device is simpler.

(3) The optical signal is incident from one side of the substrate, and the bandwidth design of the invention ensures that the signal corresponding to the blue channel is completely absorbed by the n-type blue channel absorption layer, and the signal corresponding to the red channel cannot be absorbed before reaching the n-type red channel absorption layer. Therefore, the quantum efficiency of each wave band is ensured, and the optical crosstalk is reduced.

Drawings

FIG. 1 is a schematic diagram of a two-color infrared detector in the prior art;

FIG. 2 is a schematic structural diagram of a dual color infrared detector of the present invention;

FIGS. 3-6 are flow charts illustrating the fabrication of the dual-color infrared detector of the present invention;

FIG. 7 is a schematic energy band diagram of the functional layers of the dual color infrared detector of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention are described in detail below with reference to the accompanying drawings. Examples of these preferred embodiments are illustrated in the accompanying drawings. The embodiments of the invention shown in the drawings and described in accordance with the drawings are exemplary only, and the invention is not limited to these embodiments.

It should be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and/or processing steps closely related to the scheme according to the present invention are shown in the drawings, and other details not so relevant to the present invention are omitted.

The structure of the dual-color infrared detector of the present invention is described below with reference to the accompanying drawings. As shown in fig. 2, the basic structure of the dual-color infrared detector of the present invention includes an n-type substrate 1, and a first n-type contact layer 2, an n-type blue channel layer 3, a p-type connection layer 4, an n-type red channel layer 5, and a second n-type contact layer 6, which are sequentially stacked on the n-type substrate 1. A first electrode 7 is further arranged on the first n-type contact layer 2, and a second electrode 8 corresponding to the first electrode 7 is arranged on the second n-type contact layer 6. According to the structure, the p-type connecting layer 4 of the double-color infrared detector is arranged in the middle of the whole detector, and PN junctions formed between the n-type blue channel layer 3 and the p-type connection layer 4, and between the n-type red channel layer 5 and the p-type connection layer 4 are located at both sides of the p-type connection layer 4, plus an electron barrier (corresponding to blue channel) between the n-type blue channel barrier layer 32 and the n-type blue channel absorption layer 31, and an electron barrier (corresponding to the red channel) between the n-type red channel barrier layer 51 and the n-type red channel absorber layer 52, therefore, the electronic potential barrier is maximized, the situation that when a device of one wave band works, minority carriers generated by the device absorption layer corresponding to the other wave band are difficult to cross the potential barrier is realized, and the electrical crosstalk is restrained to the maximum extent.

Based on the above basic structure, specific embodiments of the present invention are explained below.