Infrared radiation sensitive structure and method of making said structure

FIELD: physics.

SUBSTANCE: infrared radiation sensitive structure having a substrate whose top layer is made from CdTe, a 10 mcm thick working detector layer made from Hg1-xCdxTe, where x=xd=0.2-0.3, a 0.1-0.2 mcm thick insulating layer made from CdTe, and a top conducting layer with thickness of approximately 0.5 mcm also has a 0.5-6.0 mcm thick lower variband layer between the substrate and the detector layer, where the said variband layer is made from Hg1-xCdxTe, where the value of x gradually falls from a value in the range of 1-(xd+0.1) to a value xd, between the working detector layer and the insulating layer, a top variband layer with thickness of 0.03-1.00 mcm made from Hg1-xCdxTe where the value of x gradually increases from a value xd to a value in the range of 1-(xd+0.1), and dielectric layers between the insulating layer and the top conducting layer. Disclosed also is a method of making the said structure.

EFFECT: possibility of making a highly stable infrared sensitive structure with broad functional capabilities.

12 cl, 1 dwg

 

The invention relates to an infrared technique and technology of infrared imaging devices, specifically to a photodetector devices of the infrared wavelength range and their manufacturing techniques.

A known structure of HgCdTe MIS-device [1], containing layers of HgCdTe and CdTe and having in its composition CdTe-HgCdTe-heterojunction and passivating dielectric protective layer consisting of a material having a wider forbidden area than the semiconductor material of the detector layer of HgCdTe. Dielectrics under the metal shutter can be SiO2and Si3N4formed by deposition from the gas phase, or other suitable dielectric is deposited at a relatively low temperature. Passivating layer has a thickness of from 50 to 100 nm. It is grown in the same device as the substrate, for example, by molecular beam epitaxy (MBE) or chemical deposition from the gas phase ORGANOMETALLIC compounds (in a single technological cycle). High quality passivation and high quality CdTe layer due to the implementation of coherent crystalline structures and prevent atmospheric contamination of the semiconductor structure during the growth of layers in a single technological cycle. It is assumed that the passivating layer CdTe impervious to diffusion of impurities through h the th. The disadvantage of this structure is that the lack of between the substrate and pestiviruses intermediate layer graded-gap layer is not possible to agree on regular lattices of the substrate of HgCdTe and pestiviruses layer of CdTe, which leads to the appearance of surface States at the interface of HgCdTe-CdTe and adversely affect such characteristics of charge-coupled devices (CCD)as the storage time and the transfer efficiency of charges is made on the basis of such patterns. In addition, in the absence of matching graded-gap layers may cause significant fixed charges in CdTe, which leads to an increase of operating voltages and moving charges, which cause instability of the operating characteristics of the device.

A known structure of an infrared (IR) photoresistor [2], containing layers of CdTe, HgCdTe and CdTe, which was made on the basis grown by MBE CdTe heterostructures/Hg1-xCdxTe at x=0,36. Fabrication of heterostructures was performed in a single process on a substrate undoped gallium arsenide with orientation (211)and included the following steps: growing a buffer layer of CdTe thickness of 1.5 μm on a substrate of GaAs, grown on a buffer layer of CdTe layer Hg1-xCdxTe, where x=0.36 and at a temperature of 185°C for 2 hours with a speed of 1.5 mm/h, and growing the top is about pestiviruses CdTe layer on the layer of HgCdTe. The disadvantages of such a photoresistor and method of its manufacture is the fact that the growth of the heterostructures was performed without changing the temperature regime during all operations for one of the composition of the HgCdTe layer. It was not possible to control the spectral range of photosensitivity, limited the possibility of creating other options photodetectors limited the possibility of controlling the properties of the grown buffer layers of layers of CdTe and HgCdTe and not allowed to affect the quality of the interfaces. In such a structure without matching graded-gap layers high likelihood of appreciable density of surface States, large fixed and mobile charges, which leads to performance deterioration of the device caused by the recombination of charge carriers at heterojunctions.

Closest to the photosensitive IR-radiation structure and method of its manufacture in relation to the inventive structure and method of its manufacture are described in [3]. Structure-prototype contains consistently United substrate thickness of about 0.25 mm, made of CdTe, the narrow-working crystal layer thickness of about 10 μm, made of HgCdTe, wide-gap gate layer with a thickness of 0.1 to 1.0 μm, made of HgCdTe, an insulating layer with a thickness of 0.1-0.2 μm, made of CdTe, and transparent the output for IR-radiation of the sealing layer thickness of about 0.5 μm, made of HgCdTe and role of the metal electrode. This structure is intended for frontal illumination through the packing layer and is typically used as a structure-type metal-dielectric-conductor (MOS), in which the wide bandgap HgCdTe layer is used as a region for accumulating and reading photogenerated charge carriers. Prototype method includes polishing a substrate, made of CdTe, transferred into a vacuum chamber which contains the evaporators Hg, Te and CdTe designed for manufacturing method of MBE layers of HgCdTe and CdTe, growing a layer of narrow-gap HgCdTe thickness of about 10 μm on a substrate of CdTe, the growing layer of wide bandgap HgCdTe thickness of from 0.1 to 1.0 μm on the narrow-gap layer, growing an insulating CdTe layer thickness of from 0.1 to 0.2 μm on the layer of wide bandgap HgCdTe and growing transparent to infrared radiation shutter HgCdTe layer thickness of about 0.5 μm on the layer of CdTe. Epitaxial growth layer is produced by deposition of mercury, tellurium and/or cadmium telluride on the substrate heated to 200°C. the temperatures of the sources of effusion of about 200°C for Hg, about 400°C for Those and about 700°C for CdTe.

The disadvantages of the structure of the prototype, manufactured by the method of the prototype, should be considered a violation of the spatial periodicity of the crystal lattices at the boundaries between materials with different constant is of ECETOC, in particular at the boundary of the substrate and the narrow-working crystal layer (which is a hindrance to this structure, when light it from the back side) and on the border of the wide-gap gate layer and the insulating layer, the formation of surface States and the emergence of fixed and mobile charges, the surface curvature of the zones, the appearance of the surface of conductive channels and surface leakage currents, the tunneling of charge carriers through the impurity levels. This leads to instability of the parameters (including the signal, threshold, noise) are made on the basis of such patterns of instruments in the course of their operation, reduces the operating temperature range, leads to hysteresis phenomena, the increase of working voltages. At high density of surface States background illumination, changing the charge on the surface States lead to instability voltage flat zones.

The goal towards which aims proposed solution is the creation of a highly photosensitive to IR radiation patterns with enhanced functionality that can be used in different PC photodetector devices, in particular in the matrices of MIS-structures (in CCD structures), photoresistor and photodiode matrix.

The solution of this problem to thetsa fact, what photosensitive to the infrared radiation of a structure containing a substrate, the top layer of which is formed of CdTe, work crystal layer thickness of about 10 μm, is made from Hg1-xCdxTe, where x=xd=0,2-0,3, an insulating layer with a thickness of 0.1-0.2 μm, made of CdTe, and the upper transparent to infrared radiation, conductive layer with a thickness of about 0.5 μm, added situated between the substrate and the crystal layer of the lower graded-gap layer thickness of 0.5 to 6.0 μm, made from Hg1-xCdxTe, in which the x value is gradually decreased from the values of x that are within a 1-(xd+0,1), to the value of xdlocated between the working crystal layer and the insulating layer of the upper graded-gap layer with a thickness of 0.03 to 1.00 μm, made from Hg1-xCdxTe, in which the value of x gradually increases from the value of xdto values that are within a 1-(xd+0,1), and dielectric layers located between the insulating layer of CdTe and the upper conductive layer.

In particular, if the base substrate is made of GaAs and deposited ZnTe layer with a thickness of 0.01 to 1.00 μm and the CdTe layer thickness of 4.0-7.0 µm, included in the substrate.

In particular, if the base substrate is made of Si and deposited ZnTe layer with a thickness of 0.01 to 1.00 μm and the CdTe layer thickness of 4.0-7.0 µm, included in the substrate.

In frequent the om case, the base substrate is made of ZnCdTe and deposited ZnTe layer with a thickness of 0.03-of 0.30 μm and a CdTe layer thickness of 5.0-8.0 µm, included in the substrate.

In particular, if the base substrate is made of Al2O3and deposited CdTe layers with a thickness of 3-5 μm, which is part of the substrate.

In particular, if the base substrate is made of ZnCdTe and deposited CdTe layer thickness of 0.1 to 1.0 μm, which is part of the substrate.

In particular, if the substrate is made of CdTe.

In the particular case between an insulating layer of CdTe and the upper conductive layer deposited dielectric layer of thickness 0,07-0,20 μm, made of SiO2and dielectric layer thickness 0.03-of 0.50 μm, made of Si3N4.

In the particular case between an insulating layer of CdTe and the dielectric layer of SiO2deposited dielectric layer with thickness of 0.1-0.2 μm of ZnTe.

The solution of this problem is achieved by the fact that in the method of manufacturing photosensitive to infrared radiation patterns, including preparation of substrate, the upper layer which contains CdTe, to the application of a subsequent layer, and application in the growth chamber by molecular-beam epitaxy crystal layer from Hg1-xCdxTe thickness of about 10 μm, where xd=0.2 and 0.3, and an insulating layer of CdTe thickness of 0.1 to 0.2 μm, in the growth chamber on a substrate in a single process consistently applied lower graded-gap layer thickness of 0.5 to 6.0 microns of Hg1-xCdxTe, det is corny layer, the upper graded-gap layer with a thickness of 0.03 to 1.00 micron of Hg1-xCdxTe and the insulating layer, the value of x for the lower graded-gap layer is gradually reduced from the values of x that are within a 1-(xd+0,1), to the value of xdand the value of x for the upper graded-gap layer gradually increase from the values of xdto values that are within a 1-(xd+0,1), then the semiconductor structure being taken out from the growth chamber and the upper surface of one of the low-temperature methods applied dielectric layer thickness 0,07-0,10 µm of SiO2, dielectric layer thickness 0.03-0,50 ám of Si3N4and the upper conductive layer with a thickness of about 0.5 micron.

In the particular case before removal of the semiconductor structure from the growth chamber on the insulation layer of CdTe is applied dielectric layer with thickness of 0.1-0.2 μm of ZnTe.

In the particular case of application of the lower and upper graded-gap layer and the detector layer is carried out at a temperature of the substrate being in the range of 170-190°C, and the growth rate of layers of 1.0 to 3.5 μm/h, applying an insulating layer of CdTe - when the temperature of the substrate being in the range of 180-220°C, and the growth rate of the layer is 0.05 to 1.00 μm/h, and applying a dielectric layer of ZnTe carried out at a temperature of the substrate in the range of 180-240°C., and the growth rate of the layer is 0.05 to 1.00 μm/h

In the drawing image is Jena offer photosensitive to infrared radiation structure (one option), in which the base substrate is made of GaAs. The scale of the thicknesses of the various layers of the structure are taken to be arbitrary.

In the drawing: 1 - base; 2 - layer substrate containing CdTe; 3 - lower graded-gap layer made from Hg1-xCdxTe; 4 - working crystal layer made from Hg1-xCdxTe, where x=0.2 and 0.3; 5 - upper graded-gap layer made from Hg1-xCdxTe; 6 - insulating layer made of CdTe; 7 - dielectric layer made of ZnTe; 8 - dielectric layer made of SiO2; 9 - dielectric layer made of Si3N4; 10 - upper conductive layer; 11 - base substrate is made of GaAs; 12 - layer, made of ZnTe.

Optical input of the photosensitive device, made on the basis of the proposed structure may be located on the side of the substrate 1 and the upper conductive layer 10. The base substrate 11 may also be made of ZnCdTe, and it may be covered with a layer 12 of ZnTe, or the entire substrate 1 may be made of CdTe.

The proposed structure can be used in the CCD, the photoresistors and photodiodes.

As the basis of the CCD of the proposed structure is used as follows. The upper conductive layers of the CCD is composed of a mix of individual electrodes 10, with interelectrode gaps between them do not exceed not the how many microns. Rear electrical contact is created to crystal layer after local removal of dielectrics 7-9, the insulating layer 6 and the upper graded-gap layer 5. Between the upper conductive electrodes and the rear contact applied voltage pulses, resulting in the depletion layer 5 and the surface of the detector layer 4 major carriers. The irradiation of the semiconductor structure through the substrate 1, or through the upper conductive layers 10 IR radiation with a wavelength sufficient to interband generation of charge carriers in the detector layer 4 are electron-hole pairs, which are separated by the electric field. The irradiation of the semiconductor structure through the substrate 1 in it reduces the loss of carriers associated with their recombination at the interface between the layer of CdTe 2 and the lower graded-gap layer 3, due to the lower density of surface States at this boundary. Minority charge carriers are accumulated in the potential wells located in the upper graded-gap layer 5 (on the surface of the graded-gap layer or at some distance from its surface, depending on the profile of the values of x in Hg1-xCdxTe graded-gap layer 5 and attached to the upper conductive layers 10 strains). The accumulated charge packets of minority carriers carry the information about the intensity of radiation in the area is s separate electrodes. The time savings can be significant due to the fact that the potential well is located at the top graded-gap layer 5, where the dark current generation of minority carriers is much less than in the detector layer. After accumulation of the charges, it may be read by changing the control voltage on the top electrode or electrodes formed on the top insulating CdTe layer 6. Under the action of these stresses charge packets are shifted along the surface of the structure and read out through the output device that is connected to the CCD. The transfer efficiency of the charge packets in the proposed structure will be higher than in the structure of the prototype, due to the low density of surface States on the border of the insulating layer 6 and the upper graded-gap layer 5, and the working voltage will be less due to the lower stresses flat areas controlled by the introduction of a compensating fixed charge in the dielectric layers 7-9.

The proposed structure as a photoresistor is used as follows. Photoresistor acts as a resistance, the value of which depends on the intensity of radiation of the appropriate wavelength. The upper conducting layer 10 applied voltage (positive or negative bias depending on the conductivity type crystal layer) relative to casin mitralnogo crystal layer, which leads to the depletion of minority carriers charge the surface area of the upper graded-gap layer 5 and the detector layer 4. The same effect can be achieved by controlled introduction of dielectric layers 7-9 fixed charge. The presence of the upper graded-gap layer 5 and/or the presence of an electric field created by the potential difference between the electrode 10 and at the detector layer, prevents recombination of minority carriers at the interface of the insulating layer 6 and the upper graded-gap layer 5. Note that the surface recombination in the proposed structure will be low due to the low density of surface States, due to the approval of permanent gratings in the upper graded-gap layer 5 and the insulating layer 6. The reduction of surface recombination leads to an increase in the lifetime of nonequilibrium (created by radiation) charge carriers in the semiconductor volume and increase the sensitivity of the photoresistor. Approval of permanent gratings in the upper graded-gap layer 5 and insulating layer 6 increases the stability of the characteristics. This results in the use of protective dielectric coatings 7-9. The proposed structure allows to increase the sensitivity and stability characteristics of the photoresistor.

As photodiode PR is llorenna structure is used as follows. The exposed dielectric layers 6-9 on the outer side conductive layer 10, and are created (for example, by ion implantation) from the upper surface of the detector layer region with the opposite detector layer, the conductivity type of the semiconductor. The infrared radiation of the appropriate wavelength creates electron-hole pairs, which are separated by a potential barrier between the n - and p-regions working detector layer. An important characteristic of the photodiode is dark resistance of the n-p transition. In the proposed structure of this resistance is large due to the small magnitude of the surface current leakage (when high-quality interface between the insulating layer 6 and the upper graded-gap layer 5, the surface current leakage is small). Small voltage flat areas with the introduction of a compensating fixed charge in the dielectric layers 7-9 also lead to a decrease in conductivity along the surface of the partition environments. Layers 7-9 provide the stability characteristics of the photodiode due to the protection of the interface between the insulating layer 6 and the upper graded-gap layer 5 from unwanted external influences (for example, atmospheric pollution).

Proposed photosensitive to IR-radiation structure and method of its manufacture allow you to create a number of highly stable devices: CCD structure with a large in Eminem storage and high transfer efficiency, the photoresistors and photodiodes with high sensitivity and high informatika resistance. The advantage of the proposed structure is the possibility lighting her front and rear.

Sources of information

1. Pat. U.S. No. 4885619, U.S. class: 357/24, IPC: H01L 29/78; Appl. 16.05.1989, publ. 05.12.1989.

2. Yuan S., L. He, J. Yu, M. Yu, Qiao Y., Zhu J. Infrared photoconductor fabricated with a molecular beam epitaxially grown CdTe/HgCdTe heterostructure, Appl. Phys. Lett., 1991, V.58(9), P.914-916.

3. Pat. U.S. No. N, U.S. class: 257/78, IPC: H01L 31/18; Appl. 13.07.1989, publ. 05.03.1991 prototype.

1. Photosensitive to infrared radiation structure containing a substrate, the top layer which contains CdTe, work crystal layer thickness of about 10 μm, is made from Hg1-xCdxTe, where x=xd=0,2-0,3, an insulating layer with a thickness of 0.1-0.2 μm, made of CdTe, and the upper transparent to infrared radiation conductive layer with a thickness of about 0.5 μm, characterized in that it additionally located between the substrate and the crystal layer of the lower graded-gap layer thickness of 0.5 to 6.0 μm, made from Hg1-xCdxTe, in which the value of x gradually decreases from values that are within a 1-(xd+0,1), to the value of xdlocated between the working crystal layer and the insulating layer of the upper graded-gap layer with a thickness of 0.03 to 1.00 μm, made from Hg1-xCdxTe, in which value is x gradually increases from the value of x dto values that are within a 1-(xd+0,1), and dielectric layers located between the insulating layer of CdTe and the upper conductive layer.

2. The structure according to claim 1, characterized in that the base substrate is made of GaAs and deposited ZnTe layer with a thickness of 0.01 to 1.00 μm and the CdTe layer thickness of 4.0-7.0 µm, included in the substrate.

3. The structure according to claim 1, characterized in that the base substrate is made of Si and deposited ZnTe layer with a thickness of 0.01 to 1.00 μm and the CdTe layer thickness of 4.0-7.0 µm, included in the substrate.

4. The structure according to claim 1, characterized in that the base substrate is made of ZnCdTe and deposited ZnTe layer with a thickness of 0.03-of 0.30 μm and a CdTe layer thickness of 5.0-8.0 µm, included in the substrate.

5. The structure according to claim 1, characterized in that the base substrate is made of Al2O3and deposited CdTe layers with a thickness of 3-5 μm, which is part of the substrate.

6. The structure according to claim 1, characterized in that the base substrate is made of ZnCdTe and deposited CdTe layer thickness of 0.1 to 1.0 μm, which is part of the substrate.

7. The structure according to claim 1, characterized in that the substrate is made of CdTe.

8. The structure according to claim 1, characterized in that between the insulating layer of CdTe and the upper conductive layer deposited dielectric layer of thickness 0,07-0,20 μm, made of SiO2and dielectric layer thickness 0.03-of 0.50 μm, made of Si3N4 .

9. Structure of claim 8, characterized in that between the insulating layer of CdTe and the dielectric layer of SiO2deposited dielectric layer with thickness of 0.1-0.2 μm of ZnTe.

10. A method of manufacturing a photosensitive to infrared radiation patterns, including preparation of substrate, the upper layer which contains CdTe, to the application of a subsequent layer and application in the growth chamber by molecular-beam epitaxy crystal layer from Hg1-xCdxTe thickness of about 10 μm, where x=xd=0.2 and 0.3, and an insulating layer of CdTe thickness of 0.1-0.2 μm, characterized in that in the growth chamber on a substrate in a single process consistently applied lower graded-gap layer thickness of 0.5 to 6.0 microns of Hg1-xCdxTe crystal layer, the upper graded-gap layer with a thickness of 0.03 to 1.00 micron of Hg1-xCdxTe and an insulating layer, with the value of x for the lower graded-gap layers gradually decrease from values that are within a 1-(xd+0,1), to the value of xdand the value of x for the upper graded-gap layer gradually increase from the values of xdto values that are within a 1-(xd+0,1), then the semiconductor structure being taken out from the growth chamber and the upper surface of one of the low-temperature methods applied dielectric layer thickness 0,07-0,10 µm of SiO2dielectrics the s layer thickness 0.03-0,50 ám of Si 3N4and the upper conductive layer with a thickness of about 0.5 micron.

11. The method according to claim 10, characterized in that, before the removal of the semiconductor structure from the growth chamber on the insulation layer of CdTe is applied dielectric layer with thickness of 0.1-0.2 μm of ZnTe.

12. The method according to claim 11, characterized in that the deposition of the lower and upper graded-gap layer and the detector layer is carried out at a temperature of the substrate being in the range of 170-190°C, and the growth rate of layers of 1.0 to 3.5 μm/h, applying an insulating layer of CdTe - when the temperature of the substrate being in the range of 180-220°C, and the growth rate of the layer is 0.05 to 1.00 μm/h, and applying a dielectric layer of ZnTe carried out at a temperature of the substrate in the range of 180-240°C., and the growth rate of the layer is 0.05 to 1.00 μm/H.



 

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8 cl, 6 dwg

FIELD: physics, semiconductors.

SUBSTANCE: invention relates to microelectronics and can be used in designing semiconductor ultraviolet radiation sensors. A semiconductor UV radiation sensor has a substrate on which there are series-arranged wiring layer made from TiN, a photosensitive AlN layer, and an electrode system which includes a platinum rectifying electrode which is semi-transparent in the C-region of UV radiation, connected to the AlN layer to form a Schottky contact, first and second leads for connecting to an external measuring circuit, where the first lead is connected to the wiring layer and the second to the rectifying electrode. The method of making a semiconductor UV radiation sensor involves successive deposition of a wiring TiN layer and a photosensitive AlN layer onto a substrate through reactive magnetron sputtering on a general processing unit in a nitrogen-containing gas medium with subsequent formation of a platinum rectifying electrode which is semitransparent in the C-region of UV radiation, connected to the photosensitive AlN layer to form a Schottky contact, and leads for connecting the rectifying electrode and the wiring layer to an external measuring circuit. The wiring and photosensitive layers are deposited continuously without allowing cooling down of the substrate. The platinum rectifying electrode is made through three-electrode ion-plasma sputtering of a platinum target at pressure of 0.5-0.6 Pa for 4-6 minutes, target potential of 0.45-0.55 kV and anode current of 0.8+1.2 A. Sensitivity of the end product is equal to 65-72 mA/W.

EFFECT: increased sensitivity of the end product.

2 cl, 2 dwg, 1 tbl

FIELD: physics.

SUBSTANCE: infrared radiation sensitive structure having a substrate whose top layer is made from CdTe, a 10 mcm thick working detector layer made from Hg1-xCdxTe, where x=xd=0.2-0.3, a 0.1-0.2 mcm thick insulating layer made from CdTe, and a top conducting layer with thickness of approximately 0.5 mcm also has a 0.5-6.0 mcm thick lower variband layer between the substrate and the detector layer, where the said variband layer is made from Hg1-xCdxTe, where the value of x gradually falls from a value in the range of 1-(xd+0.1) to a value xd, between the working detector layer and the insulating layer, a top variband layer with thickness of 0.03-1.00 mcm made from Hg1-xCdxTe where the value of x gradually increases from a value xd to a value in the range of 1-(xd+0.1), and dielectric layers between the insulating layer and the top conducting layer. Disclosed also is a method of making the said structure.

EFFECT: possibility of making a highly stable infrared sensitive structure with broad functional capabilities.

12 cl, 1 dwg

FIELD: physics.

SUBSTANCE: method of reducing spectral density of photodiode diffusion current fluctuation in high frequency range involves applying reverse bias V across a p-n junction with a short base and a blocking contact to the base, said reverse bias satisfying the conditions 3kT < q|V| < Vb,t and 3kt < q|V| < Vb,a, where: k is Boltzmann constant; T is temperature; q is electron charge; Vb,t is tunnel breakdown voltage; Vb,a is avalanche breakdown voltage.

EFFECT: disclosed method enables to increase the signal-to-noise ratio of the photodiode in the high frequency range by reducing spectral range of diffusion current fluctuation.

4 dwg

FIELD: physics.

SUBSTANCE: high signal-to-noise (S/N) ratio infrared photodiode has a heavily doped layer (1) of a main p-n junction, a heavily doped layer (2) of an additional p-n junction, a padded base (3) for the main and additional p-n junctions and a substrate (5). The common base (3) has a space-charge region (4) for the main p-n junction. An ohmic contact (6, 7, 8) is formed for each of the layers of the structure. The total thickness of the heavily doped layer of the main p-n junction and the space-charge region of the main p-n junction lying in the common base satisfies a condition defined by a mathematical expression. To increase the S/N ratio in the infrared photodiode, diffusion current of the additional p-n junction and the sum of the diffusion current and photocurrent of the main p-n junction are recorded, and the diffusion current of the additional p-n junction is then used for correlation processing of the signal and noise of the main p-n junction. S/N ratio in the infrared photodiode is increased by using diffusion current of the additional p-n junction, whose noise is correlated with noise of the diffusion current of the main (infrared radiation detecting) p-n junction, for correlation processing of the signal and noise of the main p-n junction.

EFFECT: high signal-to-noise ratio of the infrared photodiode.

2 cl, 2 dwg

FIELD: physics.

SUBSTANCE: inventions can be used in threshold photodetectors for detecting weak electromagnetic radiation in the infrared range. The high signal-to-noise ratio infrared photodiode has a heavily doped layer adjacent to a substrate which is transparent for infrared radiation, whose thickness l1 satisfies the condition: and a weakly doped layer of another conductivity type (base), whose thickness d satisfies the condition d<L. Ohmic contacts are formed along two opposite sides of the periphery of the weakly doped layer. To increase the signal-to-noise ratio in the infrared photodiode, the sum of diffusion current and photocurrent of the p-n junction, and current of the longitudinal conductance of the base, which flows between ohmic contacts formed along two opposite sides of the periphery of the weakly doped layer, is determined, while applying a small voltage across said contacts, which satisfies a given condition.

EFFECT: invention increases the signal-to-noise ratio of the infrared photodiode by using current of longitudinal conductance of the base, whose noise is correlated with noise of the diffusion current of the p-n junction, for correlated processing of the signal and the noise of the p-n junction which detects infrared radiation.

2 cl, 3 dwg

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