阅读说明：本技术 一种多层InGaAs探测器材料结构和制备方法 (Multilayer InGaAs detector material structure and preparation method ) 是由 顾溢 王红真 杨波 马英杰 李淘 邵秀梅 李雪 龚海梅 于 2019-11-11 设计创作，主要内容包括：本发明公开了一种多层InGaAs探测器材料结构和制备方法：所述探测材料结构由下往上依次为InP(001)衬底、n型InP缓冲层、i型晶格匹配的InGaAs吸收层、n型晶格匹配的InGaAs阻挡层和n型InP帽层。其中,所述的n型阻挡层的厚度为40nm～200nm,其掺杂浓度5x10<Sup>15</Sup>cm<Sup>-3</Sup>～5x10<Sup>17</Sup>cm<Sup>-3</Sup>,其材料为与InP晶格匹配的InGaAs。制备方法为依次分子束外延生长即可。本发明的InGaAs探测材料增加的n型阻挡层能够有效实现对扩散成结工艺的控制。(The invention discloses a multilayer InGaAs detector material structure and a preparation method thereof, wherein the multilayer InGaAs detector material structure comprises the following steps: the detection material structure sequentially comprises an InP (001) substrate, an n-type InP buffer layer, an i-type lattice-matched InGaAs absorption layer, an n-type lattice-matched InGaAs barrier layer and an n-type InP cap layer from bottom to top. Wherein the thickness of the n-type barrier layer is 40 nm-200 nm, and the doping concentration is 5x10 15 cm ‑3 ～5x10 17 cm ‑3 The material is InGaAs lattice-matched to InP. The preparation method comprises sequential molecular beam epitaxial growth. The n-type barrier layer added to the InGaAs detection material can effectively realize the control of the diffusion junction forming process.)

1. A multilayer InGaAs detector material structure is characterized in that: the detection material structure sequentially comprises an InP (001) substrate, an n-type InP buffer layer, an i-type lattice-matched InGaAs absorption layer, an n-type lattice-matched InGaAs barrier layer and an n-type InP cap layer from bottom to top.

2. The structure of claim 1, wherein the InP (001) substrate is a semi-insulating InP (001) single crystal substrate or an N-type InP (001) single crystal substrate.

3. The multilayer InGaAs detector material structure of claim 1, wherein the n-type InP buffer layer has a doping concentration of 1x10¹⁶cm^-3～1x10¹⁸cm^-3。

4. The multilayer InGaAs detector material structure of claim 1, wherein the i-type lattice-matched InGaAs absorption layer has a doping concentration of 1x10¹⁴cm^-3～1x10¹⁵cm^-3。

5. The multilayer InGaAs detector material structure of claim 1, wherein the n-type lattice-matched InGaAs barrier layer has a thickness of 40nm to 200nm and a doping concentration of 5x10¹⁵cm^-3～5x10¹⁷cm^-3。

6. The multilayer InGaAs detector material structure of claim 1, wherein the n-type InP cap layer has a doping concentration of 5x10¹⁵cm^-3～1x10¹⁷cm^-3。

7. A method of fabricating the multilayer InGaAs detector material structure of claim 1, characterized by the following method steps:

(1) heating the InP (001) substrate to an analysis temperature, deoxidizing, then cooling to an InP growth temperature, and growing an n-type InP buffer layer;

(2) heating the substrate to a growth temperature, and growing an i-type lattice-matched InGaAs absorption layer;

(3) continuously growing an n-type lattice-matched InGaAs layer as a diffusion barrier layer;

(4) cooling the substrate to the growth temperature, and growing an n-type InP cap layer;

(5) and completing the preparation of the multilayer InGaAs detector material.

Technical Field

The invention belongs to the field of semiconductor photoelectronic devices, and particularly relates to a multilayer InGaAs detector material structure and a preparation method thereof.

Background

There are many important applications for the near infrared band. For example, silica fiber is in the low loss and low dispersion windows at 1.31 microns and 1.55 microns, respectively, and lasers and detectors at these two wavelengths are widely used in long wave fiber communication. The InGaAs detector is widely applied to optical fiber communication systems due to its good performance, and plays an important role in the current information age. The InP-based InGaAs material has the advantages of high absorption coefficient, high mobility, good physical and chemical stability and radiation resistance, and the prepared detector has the advantages of high working temperature, high quantum efficiency, high sensitivity, good radiation resistance and the like, and is an important choice for short-wave infrared detectors. The InGaAs short-wave infrared detector also has great potential and application prospect in the fields of space remote sensing, such as resource investigation, atmospheric composition analysis, deep space exploration and the like. The development direction of the InGaAs detector mainly lies in 2 aspects: one is to improve the device performance and increase the scale of the focal plane; secondly, the method develops to a wider detection spectrum, the short wave direction is expanded to a visible light range, and the long wave direction is developed to a wavelength of 3 mu m. In recent years, many efforts are made in various countries to improve the scale and performance level of the focal plane array of the near-infrared InGaAs detector, and most company units have the capability of preparing large area arrays. The center distance of the large area array is between 12.5 mu m and 20 mu m, and the large area array is excellent in aspects of detectivity, noise, quantum efficiency, effective pixel rate and the like. The signal-to-noise ratio is a core performance index of the near-infrared InGaAs focal plane, and is of great importance for reducing noise, improving the signal-to-noise ratio and improving the imaging quality of the infrared focal plane assembly. Research institutions at home and abroad make many efforts to reduce the noise of the InGaAs focal plane. The noise is mainly reduced through the optimization of a circuit structure and the reduction of dark current density.

The focal plane noise mainly comes from focal plane coupling noise and detector noise, and under the condition that circuit parameters are determined, the focal plane coupling noise determines the background noise level of a focal plane under short integration time, the focal plane coupling noise is influenced by a detector capacitor, and the detector capacitor is directly influenced by the doping concentration of an epitaxial material absorption layer; detector noise is affected by detector dark current, which determines the total noise level of the focal plane at long integration times. As can be seen from the influence factors of the focal plane noise, the absorption layer epitaxial material with low doping concentration has great help to reduce the focal plane noise.

However, the diffusion junction formation process of the multilayer InGaAs/InP detection epitaxial material with the low doping concentration of the absorption layer has the problem that the junction position cannot be controlled. Since the doping concentration of the InGaAs absorption layer is low, when the InP cap layer is p-type diffused, p-type impurities easily enter the InGaAs absorption layer, and the diffusion depth is difficult to accurately control. Therefore, innovations on the corresponding multilayer InGaAs/InP detection material structure and the preparation method are needed to provide help for accurately controlling the p-type diffusion depth of the InP cap layer.

Disclosure of Invention

The invention aims to solve the technical problem of providing a multilayer InGaAs detector material structure and a preparation method thereof, wherein the material structure can effectively realize the control of a diffusion junction forming process.

The multilayer InGaAs detector material structure sequentially comprises an InP (001) substrate, an n-type InP buffer layer, an i-type lattice-matched InGaAs absorption layer, an n-type lattice-matched InGaAs barrier layer and an n-type InP cap layer from bottom to top.

The InP (001) substrate is a semi-insulating InP (001) single crystal substrate or an N-type InP (001) single crystal substrate.

The n-type InP buffer layer has a doping concentration of 1x10¹⁶cm^-3～2x10¹⁸cm^-3。

The doping concentration of the i-type lattice-matched InGaAs absorption layer is 1x10¹⁴cm^-3～1x10¹⁵cm^-3。

The thickness of the n-type lattice-matched InGaAs barrier layer is 40 nm-200 nmDoping concentration of 5x10¹⁵cm^-3～5x10¹⁷cm^-3。

The doping concentration of the n-type InP cap layer is 5x10¹⁵cm^-3～1x10¹⁷cm^-3。

The preparation method of the multilayer InGaAs detector material comprises the following steps:

(1) heating the InP (001) substrate to an analysis temperature, deoxidizing, then cooling to an InP growth temperature, and growing an n-type InP buffer layer;

(2) heating the substrate to a growth temperature, and growing an i-type lattice-matched InGaAs absorption layer;

(3) continuously growing an n-type lattice-matched InGaAs layer as a diffusion barrier layer;

(4) and cooling the substrate to the growth temperature, and growing the n-type InP cap layer.

(5) And completing the preparation of the multilayer InGaAs detector material.

Advantageous effects

The invention provides a multilayer InGaAs detector material structure and a preparation method, and the convenient control of the InGaAs detector diffusion junction forming process is realized through the structural design of an n-type lattice-matched InGaAs barrier layer; the preparation method can also be popularized to other material structure designs with special requirements on the diffusion and junction forming process, and has good universality.

Drawings

FIG. 1 is a schematic diagram of the structure of a multilayer InGaAs detector material of the present invention.

Detailed Description

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.