CN115513315A - High-saturation-threshold mercury cadmium telluride detector chip and preparation method thereof - Google Patents

High-saturation-threshold mercury cadmium telluride detector chip and preparation method thereof Download PDF

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CN115513315A
CN115513315A CN202211112869.6A CN202211112869A CN115513315A CN 115513315 A CN115513315 A CN 115513315A CN 202211112869 A CN202211112869 A CN 202211112869A CN 115513315 A CN115513315 A CN 115513315A
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mercury
cadmium
tellurium
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徐国庆
王仍
焦翠灵
乔辉
储开慧
杨晓阳
李向阳
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Shanghai Institute of Technical Physics of CAS
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Abstract

The invention discloses a mercury cadmium telluride detector chip with a high saturation threshold and a preparation method thereof 1‑ x Cd x The Te component gradient layer sequentially comprises a Cd component linearly-graded Hg component along the direction departing from the substrate 1‑x Cd x Te layer and Cd component nonlinear gradual change Hg 1‑x Cd x A Te layer, wherein the Cd component x is nonlinearly gradually changed from high to low by the Cd component Hg 1‑x Cd x The upper surface of the Te layer is gradually changed to the linear gradual change Hg of Cd component 1‑x Cd x The lower surface of the Te layer. Hair brushThe n-type ion implantation layer of the bright chip is formed on Cd component nonlinear gradient Hg 1‑x Cd x In the Te layer, the strong built-in electric field introduced by the gradual change band gap reduces the accumulation of holes in a space charge region by improving the drift velocity of the holes, inhibits the diffusion movement of carriers in a p region, reduces the collection efficiency of p-n junction on photo-generated electrons in the p region, reduces the carrier concentration of the space charge region, improves the saturation threshold of a chip, and realizes the work under the zero bias voltage at room temperature.

Description

High-saturation-threshold mercury cadmium telluride detector chip and preparation method thereof
Technical Field
The invention relates to a photoelectric detector for measuring mid-infrared laser power, in particular to a mercury cadmium telluride detector chip with a high saturation threshold and a preparation method thereof.
Background
The mid-infrared laser has very high transmittance when being transmitted in the atmosphere, and can realize the effective transmission of long-distance energy, thereby having wide application prospect in the fields of photoelectric countermeasure, target identification and detection, atmospheric environment monitoring, spectrum monitoring and analysis and the like. With the increasingly intensive use of mid-infrared lasers in various fields, there is an increasing demand for mid-infrared laser-oriented power meters. Most of the currently researched laser power meters in China mainly adopt products with single channels and wavelength ranges within 400 nm-1650 nm, are not similar to foreign power meters in the aspects of performance indexes, functional diversity, technical level, working reliability, use convenience and the like, and particularly are high-grade power meter products for mid-infrared laser measurement, which are basically monopolized by foreign companies.
Photoelectric power probes are generally used for weak laser power measurement because they are easily saturated under strong light radiation. When high-power incident light irradiates the photoelectric detector, when the concentration of unbalanced minority carriers generated by the incident light is close to or exceeds the concentration of majority carriers in the original balanced state, the concentration of photogenerated carriers in the space charge region is very high, and because the mobility of holes is lower than that of electrons, a large number of holes still remained in the space charge region generate a space charge effect, the built-in electric field of the pn junction is reduced, so that the pn junction reaches the separation upper limit of an electron-hole pair, and the output current is saturated. Therefore, increasing the saturation threshold of the detector at large implants is required to reduce the space charge effect and reduce the interference of photo-generated carriers with the pn junction electric field.
Many documents at home and abroad report that the movement and distribution of current carriers are influenced by a built-in electric field generated by component gradual change, in the chip structure design of the mercury cadmium telluride detector, the built-in electric field is usually used for accelerating the movement of photon-generated minority carriers to a pn junction, and the detection performance of the mercury cadmium telluride detector is improved by increasing the diffusion length of the minority carriers and inhibiting interface or surface recombination, but the chip structure is easy to saturate when the mercury cadmium telluride detector works under the high-power light incidence.
CN111554761B discloses a detector chip, which comprises a mercury cadmium telluride film and a chip structure, wherein the chip structure comprises a pn junction, a reading circuit and an indium column, the pn junction is formed on the back surface of the mercury cadmium telluride film, the back surface of the mercury cadmium telluride film is an epitaxial initial interface during epitaxial growth of the mercury cadmium telluride film, and the reading circuit is located on the back surface side of the mercury cadmium telluride film and is connected with the pn junction through the indium column. According to the invention, the junction is formed on the back surface of the HgCdTe thin film, and the pn junction is formed in the high-component material region (namely, the epitaxial interface) on the back surface of the HgCdTe thin film, so that the leakage current of a detector chip is reduced, and the response signal of the chip is enhanced, thereby remarkably improving the working performance of the detector. The chip adopts a back incidence structure, incident light points to a high Cd group subarea from a low Cd group subarea, a large number of photon-generated carriers are generated in the low Cd group subarea of the HgCdTe thin film, a pn junction is formed in a back high-component material area (namely an epitaxial interface) of the HgCdTe thin film, and the photon-generated carriers are collected by the pn junction below an absorption area through diffusion movement. The pn junction of the chip structure is in a built-in electric field which is generated by gradient components and points to a low Cd component from a high Cd component, the electric field force borne by photominority carriers in an absorption region is opposite to the movement direction of the photominority carriers diffused to a space charge region, but the response signal of the chip structure is enhanced, which indicates that the chip structure does not effectively inhibit the movement of the photominority carriers diffused to the space charge region, and the interference of the photominority carriers to the pn junction electric field under large injection cannot be reduced.
In order to increase the saturation threshold of the detector, the detector is usually operated under a reverse bias voltage to enhance the built-in electric field of the pn junction space charge region, but a large bias voltage increases dark current and joule heat, and when the joule heat is large enough, the detector is thermally failed.
Disclosure of Invention
The invention provides a mercury cadmium telluride detector chip with a high saturation threshold and a preparation method thereof, which can work under room temperature zero bias voltage and can reduce space charge effect under high-power light incidence, aiming at the problems that the conventional mercury cadmium telluride detector chip is easy to saturate under high-power light incidence, has a low saturation threshold and the like.
The technical scheme of the invention is as follows:
a mercury cadmium telluride detector chip with a high saturation threshold comprises a substrate 1, an epoxy glue 2,p type photosensitive layer 3,n type ion injection layer 4, a passivation layer 5,n type electrode layer 6 and a p-type electrode layer 7, wherein:
the p-type photosensitive layer 3 is Hg 1-x Cd x The Te component gradient layer sequentially comprises a Cd component linearly-graded Hg component along the direction departing from the substrate 1-x Cd x Te layer 31 and Cd component nonlinear gradual change Hg 1-x Cd x The Te layer 32, the Cd component x, from high to low, changes Hg nonlinearly from the Cd component 1-x Cd x The upper surface of the Te layer 32 is gradually changed to the linear gradual change Hg of the Cd component 1-x Cd x The lower surface of the Te layer 31;
the Cd component is nonlinear and gradually changed in Hg 1-x Cd x The value range of x of the Te layer 32 satisfies that b is not more than x and not more than a, a is more than b, the maximum value of a is 0.8, the minimum value is 0.5, the maximum value of b is 0.36, the minimum value is 0.25, and the thickness is 2-4 mu m;
the n-type ion implantation layer 4 is formed on the Cd component nonlinear gradual change Hg 1-x Cd x In the Te layer 32, the top surface of the n-type ion implantation layer 4 and the Cd component are nonlinearly graded Hg 1-x Cd x The top surface of the Te layer 32 is flush, and the thickness of the n-type ion injection layer 4 is 1-1.8 mu m;
the Cd component is linearly and gradually changed into Hg 1-x Cd x The lower surface of the Te layer 31 is bonded on the substrate (1) through epoxy resin glue (2)。
Preferably, the Cd component is linearly graded Hg 1-x Cd x Te layer 31 and said Cd component non-linear gradual change Hg 1-x Cd x The p-type doping concentration of the Te layer 32 at room temperature is 1X 10 17 cm －3～ 5×10 18 cm －3 。
Preferably, the passivation layer 5 is zinc sulfide.
Preferably, the n-type electrode layer 6 is In/Au.
Preferably, the p-type electrode layer 7 is Sn/Au.
Preferably, the substrate 1 is sapphire, silicon or silicon carbide.
Correspondingly, the invention also discloses a preparation method of the mercury cadmium telluride detector chip with the high saturation threshold, which comprises the following steps:
s1, providing a tellurium-cadmium-mercury film extending on tellurium-zinc-cadmium, and fitting the infrared transmission spectrum of the extending tellurium-cadmium-mercury film through a multilayer model and a film system transfer matrix to obtain longitudinal component distribution of a Cd component in the tellurium-cadmium-mercury film along the growth direction;
s2, providing a substrate;
s3, adhering the tellurium-cadmium-mercury film extending on the tellurium-zinc-cadmium to the substrate through epoxy resin glue;
s4, removing the tellurium, zinc and cadmium through rough polishing, fine polishing and a tellurium, zinc and cadmium corrosion solution, and then corroding an interface by using a Br-HBr corrosion solution to expose the surface;
s5, forming an n-type ion implantation layer through boron ion implantation;
s6, preparing a passivation layer by using a thermal evaporation technology;
s7, preparing an n-type electrode layer by ion beam sputtering;
and S8, preparing the p-type electrode layer by using ion beam sputtering.
Compared with the traditional mercury cadmium telluride detector chip, the invention has the advantages that:
1. the space charge effect is reduced, and the saturation threshold is improved.
(1) Increasing the drift velocity of holes in the space charge region
The n-type ion implantation layer is in Cd groupPartial nonlinear gradual change of Hg 1-x Cd x In the Te layer, the drift motion of holes is accelerated by a strong built-in electric field introduced by the gradual change band gap, the accumulation of holes in the space charge region under high-power light incidence is reduced.
(2) Reducing carrier concentration in space charge region
The thickness of the n-type ion injection layer is less than the nonlinear gradual change Hg of Cd component 1-x Cd x The thickness of the Te layer and the strong built-in electric field introduced by the gradual band gap inhibit the diffusion movement of p-region carriers to the space charge region, reduce the collection efficiency of p-n junction on p-region photon-generated minority carriers, and reduce the carrier concentration of the space charge region.
2. Can work under room temperature zero bias voltage.
Drawings
FIG. 1 is a schematic diagram of a mercury cadmium telluride detector chip with a high saturation threshold according to the present invention.
FIG. 2 is a schematic diagram of the band variation of a graded layer of Hg1-xCdxTe composition according to the present invention.
FIG. 3 is a Cd composition distribution diagram of a Cd composition nonlinear graded Hg1-xCdxTe layer in example 1.
FIG. 4 is a Cd composition distribution diagram of a Cd composition nonlinear graded Hg1-xCdxTe layer in example 2.
FIG. 5 is a Cd composition distribution diagram of a Cd composition nonlinear graded Hg1-xCdxTe layer in example 3.
Fig. 6 is the photoresponse of comparative example and example 3 under laser irradiation at room temperature.
Detailed Description
The technical solutions in the embodiments of the present invention will be described in detail below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
The traditional mercury cadmium telluride detector chip aims at detecting weak signals generally, the quantum efficiency is concerned in the design, the collection efficiency of photon-generated carriers is improved, and the device is largeWhen power light is incident, it is easily saturated. In order to improve the saturation threshold of a mercury cadmium telluride detector chip, an n-type ion injection layer is formed on a Cd component nonlinear gradient Hg 1-x Cd x In the Te layer, the thickness of the n-type ion injection layer is less than the nonlinear gradual change Hg of Cd component 1-x Cd x The thickness of the Te layer and the strong built-in electric field introduced by the gradual band gap reduce the accumulation of holes in the space charge region by improving the drift velocity of the holes, and simultaneously the electric field inhibits the diffusion movement of carriers in the p region to the space charge region, reduces the collection efficiency of p-n junction on photon-generated minority carriers in the p region, reduces the carrier concentration in the space charge region, improves the saturation threshold of the chip, and realizes the work at room temperature under zero bias voltage.
As shown in FIG. 1, the HgCdTe detector chip with high saturation threshold of the invention comprises a substrate 1, an epoxy resin adhesive 2,p type photosensitive layer 3,n type ion injection layer 4, a passivation layer 5,n type electrode layer 6 and a p-type electrode layer 7, wherein the p-type photosensitive layer 3 is Hg 1- x Cd x The Te component gradient layer sequentially comprises a Cd component linearly-graded Hg component along the direction departing from the substrate 1-x Cd x Te layer 31 and Cd component nonlinear gradual change Hg 1-x Cd x Te layer 32, cd component x from high to low, hg non-linearly graded by the Cd component 1-x Cd x The upper surface of the Te layer 32 is gradually changed to the linear gradual change Hg of the Cd component 1-x Cd x The lower surface of the Te layer 31.
Hg 1-x Cd x The gradient band gap caused by the distribution of Cd component in the Te component gradient layer can be expressed as the band gap edge shift at 300K:
ΔE V ＝0.45×(1-x)(eV)
ΔE C ＝1.21×(1-x)(eV)
wherein, delta E v Is top of valence band E v Upward offset, Δ E c Bottom of guide belt E c Is offset downwardly.
Therefore, a built-in electric field formed by a graded band gap exists in the p-type photosensitive layer, and the built-in electric field generates electric field force in the same direction for electrons and holes, and the direction of the electric field force is directed to the low Cd component from the high Cd component along the incident light direction, namely to the substrate from the device surfaceAnd (4) bottom. FIG. 2 is Hg of the present invention 1-x Cd x Te composition gradient layer energy band variation diagram, hg 1-x Cd x The Te component gradient layer is obtained by growing a p-type tellurium-cadmium-mercury film on tellurium-zinc-cadmium by using a liquid phase or vapor phase epitaxy technology and then removing the tellurium-zinc-cadmium. High temperature epitaxy technique of Hg 1-x Cd x The Te component gradient layer comprises a Cd component linear gradient Hg 1-x Cd x Te layer and Cd component nonlinear gradual change Hg 1-x Cd x Te layer, wherein Cd component is nonlinearly graded Hg 1-x Cd x The Te layer has stronger built-in electric field formed by the gradually-changed band gap due to the nonlinear distribution of the Cd component.
In the invention, cd component nonlinearly gradually changes Hg 1-x Cd x The value range of x of the Te layer 32 is that b is not less than x and not more than a, a is more than b, the maximum value of a is 0.8, the minimum value is 0.5, the maximum value of b is 0.36, the minimum value is 0.25, and the thickness is 2-4 mu m. An n-type ion implantation layer 4 is formed on the Cd component nonlinear gradient Hg 1-x Cd x In the Te layer 32, the top surface of the n-type ion implantation layer 4 and the Cd component are nonlinearly graded Hg 1-x Cd x The top surface of the Te layer 32 is flush, and the thickness of the n-type ion implantation layer 4 is 1-1.8 mu m. The lattice matching at the interface of the tellurium-zinc-cadmium and tellurium-cadmium-mercury films is poor, the ion injection region is separated from the interface by utilizing Br-HBr corrosion, and a Cd component nonlinear variable layer capable of providing a stronger built-in electric field is reserved. An n-type ion implantation layer is formed on the Cd component and the Hg is non-linearly changed 1-x Cd x In the Te layer, the thickness of the n-type ion implantation layer is less than the Cd component nonlinear gradual change Hg 1-x Cd x The thickness of the Te layer is stronger, and a stronger built-in electric field promotes electrons and holes to drift towards the substrate direction, thereby influencing the movement and distribution of carriers near the space charge region. In the space charge region, the drift velocity of the holes is improved by the electric field force, the accumulation of the holes in the space charge is reduced, and the diffusion movement of carriers in a p region below the space charge region is inhibited, so that the injection efficiency of photo-generated electrons into the space charge region is low, the carrier concentration of the space charge region is reduced, the saturation threshold of a chip is improved, and the operation under room temperature and zero bias voltage is realized.
In the invention, the Cd component linearly changes Hg gradually 1-x Cd x The lower surface of the Te layer 31 is bonded to the substrate 1 by epoxy glue 2. The chip is of a normal incidence structure, and the gradual change component can influence the minority carrier diffusion length, so that the normal incidence structure can ensure that photogenerated holes generated on the n-type ion injection layer are fully collected, promote the drift of the holes to the p region, improve the collection efficiency of the photogenerated holes in the n region, and reduce the collection efficiency of the photogenerated electrons in the p region below the space charge region.
The preparation method of the mercury cadmium telluride detector chip with the high saturation threshold is further described in detail by combining the embodiment as follows:
growing p-type tellurium-cadmium-mercury films with different x values on tellurium-zinc-cadmium by a liquid phase or gas phase epitaxy technology, fitting the infrared transmission spectrum of the epitaxial tellurium-cadmium-mercury film material by utilizing a multilayer model and a film system transfer matrix, and acquiring the component distribution of a Cd component in the tellurium-cadmium-mercury film along the growth direction, wherein the calculation formula is as follows:
Figure BDA0003844259820000071
in the formula: x (z) is the composition at a distance z from the substrate interface; xs, d, S and Δ z are the surface composition, thickness, composition gradient and diffusion region width of the epitaxial layer, respectively, and erf is an error function.
In order to obtain Cd component nonlinear gradual change Hg meeting the conditions 1-x Cd x A Te layer, wherein a low Cd component surface of a p-type mercury cadmium telluride film which grows in an epitaxial mode is required to be adhered to a substrate by using epoxy resin adhesive, cadmium zinc telluride is removed to an interface by rough polishing, fine polishing and a cadmium zinc telluride corrosive liquid, and the surface is corroded by using a Br-HBr corrosive liquid, namely the Cd component is subjected to nonlinear gradual change of Hg 1-x Cd x And (3) etching the upper surface of the Te layer for time according to the component distribution of the Cd component in the obtained tellurium-cadmium-mercury film along the growth direction.
Example 1:
growing p-type tellurium-cadmium-mercury film on tellurium-zinc-cadmium by utilizing vapor phase epitaxy technology, wherein the Au doping concentration is 5 multiplied by 10 at room temperature 18 cm -3 The material composition x was calculated to be 0.21 by infrared transmission spectroscopy and the multilayer model and film system transfer matrix were usedFitting the infrared transmission spectrum to obtain the component distribution of the Cd component in the HgCdTe film along the growth direction. Sticking the p-type tellurium-cadmium-mercury film to a sapphire substrate, roughly polishing, finely polishing and removing tellurium-zinc-cadmium to an interface by using a tellurium-zinc-cadmium corrosive liquid, corroding the interface for 10s by using 0.5 percent of Br-HBr corrosive liquid, and exposing Cd component nonlinear gradual change Hg 1-x Cd x The upper surface of the Te layer is provided with Cd component which is nonlinearly gradually changed into Hg 1- x Cd x The variation range of x of the Te layer is more than or equal to 0.25 and less than or equal to 0.8, the thickness is 4 mu m, the variation distribution of the Cd component is shown in figure 3, and the maximum built-in electric field generated by the nonlinear variation of the Cd component can reach 6322V/cm.
Hg is non-linearly gradually changed in Cd component 1-x Cd x Preparing an n-type ion implantation layer on the Te layer by implanting boron ions with an implantation energy of 350keV and an implantation dosage of 1 × 10 15 cm -2 The thickness of the n-type ion implantation layer is 1.8 μm.
The passivation layer is prepared by growing zinc sulfide by thermal evaporation to a thickness of
Figure BDA0003844259820000081
Preparing an n-type electrode layer In/Au on the n-type ion implantation layer by ion beam sputtering, wherein the thickness of the n-type electrode layer is respectively
Figure BDA0003844259820000082
And
Figure BDA0003844259820000083
nonlinear gradual change of Hg in Cd component by ion beam sputtering 1-x Cd x Preparing a p-type electrode layer Sn/Au on the Te layer, wherein the thickness is respectively
Figure BDA0003844259820000084
And
Figure BDA0003844259820000085
example 2:
growing a p-type tellurium-cadmium-mercury film on tellurium-zinc-cadmium by utilizing a vapor phase epitaxy technology, wherein the doping concentration of Hg vacancy is 5 multiplied by 10 at room temperature 17 cm -3 By infrared transmissionAnd (3) calculating the material component x to be 0.33 by using a spectrum, fitting the infrared transmission spectrum by using a multilayer model and a film system transfer matrix, and obtaining the component distribution of the Cd component in the mercury cadmium telluride film along the growth direction. Sticking the p-type tellurium-cadmium-mercury film to a silicon substrate, removing tellurium-zinc-cadmium to an interface by rough polishing, fine polishing and tellurium-zinc-cadmium corrosive liquid, corroding the interface for 15s by using 0.5 percent of Br-HBr corrosive liquid, and exposing Cd component nonlinear gradient Hg 1-x Cd x The upper surface of the Te layer is provided with Cd component which is nonlinearly gradually changed into Hg 1-x Cd x The variation range of x of the Te layer is more than or equal to 0.35 and less than or equal to 0.65, the thickness is 3.1 mu m, the variation distribution of the Cd component is shown in figure 4, and the maximum built-in electric field generated by the nonlinear variation of the Cd component can reach 4621V/cm.
In Cd component, the Hg is non-linearly changed gradually 1-x Cd x Preparing an n-type ion implantation layer on the Te layer by implanting boron ions with an implantation energy of 200keV and an implantation dosage of 5 × 10 14 cm -2 The thickness of the n-type ion implantation layer is 1.5 μm.
The passivation layer is prepared by growing zinc sulfide by thermal evaporation to a thickness of
Figure BDA0003844259820000091
Preparing an n-type electrode layer In/Au on the n-type ion implantation layer by ion beam sputtering, wherein the thickness of the n-type electrode layer is respectively
Figure BDA0003844259820000092
And
Figure BDA0003844259820000093
nonlinear gradual change of Hg in Cd component by ion beam sputtering 1-x Cd x Preparing a p-type electrode layer Sn/Au on the Te layer, wherein the thickness is respectively
Figure BDA0003844259820000094
And
Figure BDA0003844259820000095
example 3:
growing p-type tellurium-cadmium-mercury film on tellurium-zinc-cadmium by utilizing vapor phase epitaxy technology, and doping Hg vacancy at room temperatureThe concentration is 1X 10 17 cm -3 Calculating the material component x to be 0.31 through the infrared transmission spectrum, and fitting the infrared transmission spectrum by utilizing a multilayer model and a film system transfer matrix to obtain the component distribution of the Cd component in the HgCdTe film along the growth direction. Sticking the p-type tellurium-cadmium-mercury film to a silicon carbide substrate, removing tellurium-zinc-cadmium to an interface by rough polishing, fine polishing and tellurium-zinc-cadmium corrosive liquid, corroding the interface for 20s by using 0.5 percent of Br-HBr corrosive liquid, and exposing Cd component nonlinear gradual change Hg 1-x Cd x Upper surface of Te layer, cd component nonlinear gradual change Hg 1- x Cd x The variation range of x of the Te layer is more than or equal to 0.36 and less than or equal to 0.5, the thickness is 2 mu m, the variation distribution of the Cd component is shown in figure 5, and the maximum built-in electric field generated by the nonlinear variation of the Cd component can reach 3281V/cm.
In Cd component, the Hg is non-linearly changed gradually 1-x Cd x Preparing an n-type ion implantation layer on the Te layer by implanting boron ions with an implantation energy of 100keV and an implantation dosage of 1 × 10 14 cm -2 The thickness of the n-type ion implantation layer is 1 μm.
The passivation layer is prepared by growing zinc sulfide by thermal evaporation to a thickness of
Figure BDA0003844259820000096
Preparing an n-type electrode layer In/Au on the n-type ion implantation layer by ion beam sputtering, wherein the thickness of the n-type electrode layer is respectively
Figure BDA0003844259820000101
And
Figure BDA0003844259820000102
nonlinear gradual change of Hg in Cd component by ion beam sputtering 1-x Cd x Preparing a p-type electrode layer Sn/Au with the thickness of respectively
Figure BDA0003844259820000103
And
Figure BDA0003844259820000104
comparative example:
a traditional tellurium-cadmium-mercury detector chip structure is adopted, pn junctions are directly formed by injection on the epitaxial p-type tellurium-cadmium-mercury thin film low Cd component surface, a tellurium-zinc-cadmium removing process is omitted, and material parameters and other device preparation processes are the same as those in embodiment 3.
The specific implementation effect is as follows:
fig. 6 shows the photoresponse of the comparative example and the example 3 irradiated by the pulsed laser with the wavelength of 3098nm and the pulse width of 200ns under 300K, and it can be clearly seen that the mercury cadmium telluride detector chip has the characteristic of high saturation threshold compared with the conventional mercury cadmium telluride detector chip.
The invention provides a mercury cadmium telluride detector chip with a high saturation threshold and a preparation method thereof, which effectively solve the problems that the mercury cadmium telluride detector chip is easy to saturate under the incidence of high-power light and the saturation threshold is low, have high industrial utilization value and have great significance for the development of domestic power meters.

Claims (7)

1. The utility model provides a mercury cadmium telluride detector chip of high saturation threshold, includes substrate (1), epoxy glue (2), photosensitive layer of p type (3), n type ion implantation layer (4), passivation layer (5), n type electrode layer (6) and p type electrode layer (7), its characterized in that:
the p-type photosensitive layer (3) is Hg 1-x Cd x The Te component gradient layer sequentially comprises a Cd component linearly-graded Hg along the direction departing from the substrate 1-x Cd x Te layer (31) and Cd component nonlinear gradual change Hg 1-x Cd x A Te layer (32) from which the Cd component x is nonlinearly graded in Hg from high to low 1-x Cd x The upper surface of the Te layer (32) is gradually changed to the linear gradual change Hg of the Cd component 1-x Cd x A lower surface of the Te layer (31);
the Cd component is nonlinear and gradually changed in Hg 1-x Cd x The value range of x of the Te layer (32) is that b is not more than x and not more than a, a is more than b, the maximum value of a is 0.8, the minimum value is 0.5, the maximum value of b is 0.36, the minimum value is 0.25, and the thickness is 2-4 mu m;
the n-type ion implantation layer (4) is formed on the Cd component nonlinear gradient Hg 1-x Cd x In the Te layer (32), the top surface of the n-type ion implantation layer (4) and the Cd component are nonlinearly graded Hg 1-x Cd x The top surface of the Te layer (32) is flush, and the thickness of the n-type ion injection layer (4) is 1-1.8 mu m;
the Cd component is linearly and gradually changed into Hg 1-x Cd x The lower surface of the Te layer (31) is bonded on the substrate (1) through epoxy resin glue (2).
2. The mercury cadmium telluride detector chip with a high saturation threshold as in claim 1, wherein: the Cd component linearly changes Hg gradually 1-x Cd x Te layer (31) and said Cd component non-linear gradual change Hg 1-x Cd x The Te layer (32) has a p-type doping concentration of 1X 10 at room temperature 17 cm －3 ～5×10 18 cm －3 。
3. The mercury cadmium telluride detector chip with a high saturation threshold as in claim 1, wherein: the passivation layer (5) is zinc sulfide.
4. The mercury cadmium telluride detector chip with a high saturation threshold as in claim 1, wherein: the n-type electrode layer (6) is In/Au.
5. The mercury cadmium telluride detector chip with a high saturation threshold as in claim 1, wherein: the p-type electrode layer (7) is Sn/Au.
6. The mercury cadmium telluride detector chip with a high saturation threshold as in claim 1, wherein: the substrate (1) is sapphire, silicon or silicon carbide.
7. A preparation method of a mercury cadmium telluride detector chip with a high saturation threshold is characterized by comprising the following steps:
1) Providing a tellurium-cadmium-mercury film extending on the tellurium-zinc-cadmium, and fitting the infrared transmission spectrum of the extending tellurium-cadmium-mercury film through a multilayer model and a film system transfer matrix to obtain the longitudinal component distribution of a Cd component in the tellurium-cadmium-mercury film along the growth direction;
2) Providing a substrate;
3) Adhering the tellurium-cadmium-mercury film on the substrate by epoxy resin adhesive;
4) Removing the tellurium, zinc and cadmium by rough polishing, fine polishing and a tellurium, zinc and cadmium corrosion solution, and then corroding an interface by using a Br-HBr corrosion solution to expose the surface;
5) Forming an n-type ion implantation layer by boron ion implantation;
6) Preparing a passivation layer by using a thermal evaporation technology;
7) Preparing an n-type electrode layer by ion beam sputtering;
8) And preparing the p-type electrode layer by ion beam sputtering.
CN202211112869.6A 2022-09-14 2022-09-14 High-saturation-threshold mercury cadmium telluride detector chip and preparation method thereof Pending CN115513315A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117133833A (en) * 2023-10-20 2023-11-28 长春理工大学 Spectrum detector chip, preparation method thereof and spectrum detector

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117133833A (en) * 2023-10-20 2023-11-28 长春理工大学 Spectrum detector chip, preparation method thereof and spectrum detector
CN117133833B (en) * 2023-10-20 2024-03-29 长春理工大学 Spectrum detector chip, preparation method thereof and spectrum detector

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