Photovoltaic infrared detector and infrared detection equipment

Abstract

The invention relates to the field of infrared detection, in particular to a photovoltaic infrared detector and infrared detection equipment, which comprises an N-type doped layer and a P-type doped layer which are stacked, the N-type doped layer and the P-type doped layer form a photoelectric detection PN junction and a voltage stabilization PN junction which are opposite in direction. The photovoltaic infrared detector works under a bias voltage, and the forward conduction direction of the voltage stabilizing PN junction is the same as the direction of the bias voltage. According to the photovoltaic infrared detector, when external bias voltage fluctuates, due to the fact that the voltage stabilizing PN junction has the voltage dividing effect, voltage fluctuation on the photoelectric detection PN junction can be weakened, output signal fluctuation caused by dark current along with bias voltage fluctuation is reduced, noise is lowered, the detection resolution of the photovoltaic infrared detector is improved, and in addition, under the illumination condition, the detection resolution of the photovoltaic infrared detector is improved. The number of carriers in the photoelectric detection PN junction is increased, and the forward resistance corresponding to the voltage stabilization PN junction is greatly reduced, so that the influence of the additional arrangement of the voltage stabilization PN junction on the light response is very small.

Description

Technical Field

[0001] The invention relates to the field of infrared detection, in particular to a photovoltaic infrared detector and infrared detection equipment. Background Art

[0002] With the development of technology, how to digitize the real environment has become more and more important in the industry. Infrared detection is one of the important ones. Among various infrared detectors, photovoltaic infrared detectors are especially favored by relevant industry insiders due to their fast response time, high impedance and low power consumption.

[0003] However, the photovoltaic infrared detectors in the prior art also face technical problems. For example, the bias voltage of the existing photovoltaic infrared detectors is often directly applied to the two ends of the corresponding working pn junction, so that the fluctuations in the bias voltage will be completely coupled to the pn junction, resulting in a significant increase in the device output noise. Specifically, since the dark current of the device is strongly related to the externally applied bias voltage, it is more obvious in medium and long-wave infrared detectors, which means that when the bias voltage provided by the readout circuit contains noise, the dark current fluctuations caused by the noise will be directly coupled to the output signal, thereby increasing the output signal fluctuations, that is, the noise increases, reducing the signal-to-noise ratio and resolution of the detector.

[0004] Therefore, how to reduce the output signal fluctuation caused by the unstable bias voltage in the photovoltaic infrared detector and improve the detection resolution has become an urgent problem to be solved by technical personnel in this field. Summary of the invention

[0005] The purpose of the present invention is to provide a photovoltaic infrared detector and infrared detection equipment to solve the problem in the prior art that the photovoltaic infrared detector has large signal noise and measurement interference due to unstable bias voltage.

[0006] In order to solve the above technical problems, the present invention provides a photovoltaic infrared detector, comprising a stacked N-type doped layer and a P-type doped layer;

[0007] The N-type doping layer and the P-type doping layer form a photoelectric detection PN junction and a voltage stabilizing PN junction in opposite directions;

[0008] The photovoltaic infrared detector operates under a bias voltage, and the forward conduction direction of the voltage-stabilizing PN junction is the same as the direction of the bias voltage.

[0009] Optionally, in the photovoltaic infrared detector, the material energy gap corresponding to the voltage-stabilizing PN junction is larger than the material energy gap corresponding to the photoelectric detection PN junction.

[0010] Optionally, in the photovoltaic infrared detector, at least one of the doping layers included in the voltage-stabilizing PN junction is arranged in a non-absorbing layer of the photovoltaic infrared detector.

[0011] Optionally, in the photovoltaic infrared detector, the photovoltaic infrared detector is a short-wave InGaAs detector;

[0012] The N-type doping layer and / or the P-type doping layer of the voltage-stabilizing PN junction is at least one of an InP doping layer, an InAlAs doping layer and an InAsP doping layer;

[0013] The voltage-stabilizing PN junction is arranged in the contact layer of the photovoltaic infrared detector.

[0014] Optionally, in the photovoltaic infrared detector, the photovoltaic infrared detector is a medium-wave InAs / InAsSb superlattice detector, or a medium-wave InAsSb bulk material detector;

[0015] The N-type doped layer and / or the P-type doped layer of the voltage-stabilizing PN junction is at least one of an InAs / InAsSb superlattice layer and an InAsSb layer;

[0016] The voltage-stabilizing PN junction is arranged in the contact layer of the photovoltaic infrared detector.

[0017] Optionally, in the photovoltaic infrared detector, the photovoltaic infrared detector is a long-wave InAs / GaSb superlattice detector or an InAs / InAsSb superlattice detector;

[0018] The N-type doping layer and / or the P-type doping layer of the voltage-stabilizing PN junction is at least one of an InAs / AlSb superlattice layer, an InAs / GaSb superlattice layer, an InAs / GaSb / AlSb / GaSb superlattice layer and an InAsSb layer.

[0019] Optionally, in the photovoltaic infrared detector, the photovoltaic infrared detector includes two P-type doping layers and one N-type doping layer;

[0020] The N-type doping layer is arranged between the two P-type doping layers.

[0021] Optionally, in the photovoltaic infrared detector, the photovoltaic infrared detector further comprises an N-type mother layer;

[0022] One of the two P-type doped layers is a P-type doped layer diffused in the N-type mother layer.

[0023] Optionally, in the photovoltaic infrared detector, the photovoltaic infrared detector includes two N-type doped layers and one P-type doped layer;

[0024] The P-type doping layer is arranged between the two N-type doping layers.

[0025] An infrared detection device, comprising a plurality of photovoltaic infrared detectors as described in any one of the above;

[0026] A plurality of the photovoltaic infrared detectors are arranged in an array.

[0027] The photovoltaic infrared detector provided by the present invention comprises a stacked N-type doped layer and a P-type doped layer; the N-type doped layer and the P-type doped layer form a photoelectric detection PN junction and a voltage-stabilizing PN junction in opposite directions; the photovoltaic infrared detector operates under a bias voltage, and the forward conduction direction of the voltage-stabilizing PN junction is the same as the bias voltage direction. The photovoltaic infrared detector of the present invention can weaken the voltage fluctuation on the photoelectric detection PN junction when the external bias voltage fluctuates, because the voltage-stabilizing PN junction has a voltage-dividing effect, thereby reducing the output signal fluctuation caused by the dark current fluctuating with the bias voltage, reducing noise, and improving the detection resolution of the photovoltaic infrared detector. In addition, under illumination conditions, the number of carriers in the photoelectric detection PN junction increases, that is, the conductivity of the photoelectric detection PN junction increases, and the corresponding resistance decreases, which will cause the voltage-dividing on the voltage-stabilizing PN junction to increase, and the forward resistance corresponding to the voltage-stabilizing PN junction will also be greatly reduced, so the effect of adding a voltage-stabilizing PN junction on the light response is very small. The present invention also provides an infrared detection device with the above-mentioned beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] FIG1 is a schematic structural diagram of a specific embodiment of a photovoltaic infrared detector provided by the present invention;

[0030] FIG2 is a schematic structural diagram of a specific embodiment of a photovoltaic infrared detector provided by the present invention;

[0031] FIG3 is a schematic structural diagram of a specific embodiment of a photovoltaic infrared detector provided by the present invention;

[0032] FIG4 is a schematic structural diagram of a specific embodiment of a photovoltaic infrared detector provided by the present invention;

[0033] FIG5 is a schematic structural diagram of a specific implementation of a photovoltaic infrared detector provided by the present invention.

[0034] In the figure, 10-bias power supply, 20-photovoltaic infrared detector, 21-photoelectric detection PN junction, 22-voltage stabilizing PN junction, 20A-first P-type InP doping layer, 20B-InGaAs material layer, 20C-N-type InP doping layer, 20D-second P-type InP doping layer, 20E-N-type InP mother layer, 20F-first N-type InAs / InAsSb superlattice doping layer, 20G-P-type InAs / InAsSb superlattice doping layer, 20H -weakly doped N or P type AlAsSb layer, 20I-weakly doped N type InAs / InAsSb superlattice layer, 20J-second N type InAs / InAsSb superlattice doped layer, 20K-N type InAs / AlSb superlattice doped layer, 20L-weakly doped P type InAs / AlSb superlattice layer, 20M-weakly doped P type InAs / GaSb superlattice layer, 20N-P type InAsSb doped layer, 20O-N type InAsSb doped layer. DETAILED DESCRIPTION

[0035] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0036] The core of the present invention is to provide a photovoltaic infrared detector, a structural schematic diagram of a specific implementation of which is shown in FIG1 , referred to as specific implementation 1, comprising a stacked N-type doped layer and a P-type doped layer;

[0037] The N-type doping layer and the P-type doping layer form a photoelectric detection PN junction 21 and a voltage stabilizing PN junction 22 in opposite directions;

[0038] The photovoltaic infrared detector 20 operates under a bias voltage, and the forward conduction direction of the voltage-stabilizing PN junction 22 is the same as the direction of the bias voltage.

[0039] Please refer to Figure 1. The photovoltaic infrared detector 20 in Figure 1 is framed by a dotted line, and a bias power supply 10 for providing the bias voltage is also provided. The photodetection PN junction 21 is also the working PN junction of the photovoltaic infrared detector 20. Further explanation is given here. The dark current in the present invention refers to the current induced by the bias power supply 10 without light excitation, and the photocurrent refers to the current excited by infrared light irradiating the photodetection PN junction 21. It should be noted that under non-illumination conditions, only the dark current flows through the photovoltaic infrared detector 20, while under illumination conditions, the dark current and the photocurrent flow through the photovoltaic infrared detector 20, and the directions of the two are the same.

[0040] Preferably, the material energy gap corresponding to the voltage-stabilizing PN junction 22 is larger than the material energy gap corresponding to the photoelectric detection PN junction 21 .

[0041] The larger energy gap of the voltage-stabilizing PN junction 22 means that it has a larger turn-on voltage when forward biased, which also means that it can receive a larger proportion of noise under the same bias.

[0042] Furthermore, at least one of the doping layers included in the voltage-stabilizing PN junction 22 is disposed on a non-absorption layer of the photovoltaic infrared detector 20 .

[0043] Of course, the voltage-stabilizing PN junction 22 is also a PN junction composed of a layer of N-type doped layer and a layer of P-type doped layer. In the preferred embodiment, it is specified that at least one of the N-type doped layer and the P-type doped layer constituting the voltage-stabilizing PN junction 22 is arranged in the non-absorption layer of the photovoltaic infrared detector 20. In order to meet the functional structure requirements of the photovoltaic infrared detector 20, the non-absorption layer usually grows an epitaxial layer whose energy gap is naturally larger than that of the absorption layer. The preferred embodiment limits the position of the epitaxial layer of the voltage-stabilizing PN junction 22, thereby realizing the limitation of the energy gap of the voltage-stabilizing PN junction 22 in the foregoing text, which greatly simplifies the production process and reduces the production cost.

[0044] As a specific implementation, the photovoltaic infrared detector 20 includes two P-type doped layers at two ends and an N-type doped layer in the middle.

[0045] Of course, in addition to the three doping layers mentioned above, an unintentionally doped or weakly n-type doped absorption layer (i.e., the InGaAs material layer 20B hereinafter) is also included between the two P-type doping layers. The absorption layer is used as a component of the photoelectric detection PN junction, and the voltage-stabilizing PN junction is composed of the PN doping layer in the material outside the absorption layer. In this specific embodiment, by sharing the N-type doping layer, at least three doping layers are required to form the photoelectric detection PN junction 21 and the voltage-stabilizing PN junction 22, which greatly reduces the space occupied by the device, and at the same time can simplify the structure inside the device and reduce costs. For corresponding reference, please refer to Figures 2 and 3.

[0046] Furthermore, the photovoltaic infrared detector 20 further includes an N-type mother layer;

[0047] One of the two P-type doped layers is a P-type doped layer diffused in the N-type mother layer.

[0048] Referring to Figure 3, the P-type doped layer located at the top in Figure 3 is obtained by diffusion in the corresponding N-type mother layer. In other words, the photoelectric detection PN junction can be formed directly by epitaxy or by diffusion after epitaxy, thereby further expanding the scope of application of the present invention.

[0049] Similarly, the photovoltaic infrared detector 20 includes two N-type doped layers at both ends and a P-type doped layer in the middle.

[0050] Of course, in this specific embodiment, an unintentionally doped or weakly p-type doped absorption layer is also included between the two N-type doped layers. However, unlike the previous text, the order in which the current flows through the two PN junctions in this specific embodiment is opposite to the order of the photovoltaic infrared detector 20 composed of the two P-type doped layers and one N-type doped layer in the previous text, but it can also achieve a voltage stabilization effect, please refer to Figures 4 and 5.

[0051] As a specific implementation, the photovoltaic infrared detector 20 is a short-wave InGaAs detector;

[0052] The N-type doping layer and / or the P-type doping layer of the voltage-stabilizing PN junction is at least one of an InP doping layer, an InAlAs doping layer and an InAsP doping layer;

[0053] The voltage-stabilizing PN junction is disposed in the contact layer of the photovoltaic infrared detector 20 .

[0054] Referring to the corresponding Figures 2 and 3, in Figure 2, from top to bottom, the first P-type InP doped layer 20A, the InGaAs material layer 20B, the N-type InP doped layer 20C and the second P-type InP doped layer 20D are included in sequence; in Figure 3, from top to bottom, the N-type InP mother layer 20E and the first P-type InP doped layer 20A, the InGaAs material layer 20B, the N-type InP doped layer 20C and the second P-type InP doped layer 20D are included in sequence. The InGaAs material layer 20B in this specific embodiment is the unintentionally doped or weakly doped absorption layer mentioned above.

[0055] As another specific implementation, the photovoltaic infrared detector 20 is a medium-wave InAs / InAsSb superlattice detector, or a medium-wave InAsSb bulk material detector;

[0056] The N-type doped layer and / or the P-type doped layer of the voltage-stabilizing PN junction is at least one of an InAs / InAsSb superlattice layer and an InAsSb layer;

[0057] The voltage-stabilizing PN junction is disposed in the contact layer of the photovoltaic infrared detector 20 .

[0058] Please refer to the corresponding Figure 4, which includes, from top to bottom, a first N-type InAs / InAsSb superlattice doped layer 20F, a P-type InAs / InAsSb superlattice doped layer 20G, a weakly doped N or P-type AlAsSb layer 20H, a weakly doped N-type InAs / InAsSb superlattice layer 20I and a second N-type InAs / InAsSb superlattice doped layer 20J. The doping concentration of the second N-type InAs / InAsSb superlattice doped layer 20J is lower than that of the first N-type InAs / InAsSb superlattice doped layer 20F, and higher than that of the weakly doped N or P-type AlAsSb layer 20H and the weakly doped N-type InAs / InAsSb superlattice layer 20I.

[0059] In addition, the above two specific implementations further limit that the voltage-stabilizing PN junction is disposed in the contact layer, and the material of the contact layer generally has a larger energy gap, can allocate a larger proportion of noise, and reduce the impact of noise.

[0060] As another specific implementation, the photovoltaic infrared detector 20 is a long-wave InAs / GaSb superlattice detector or an InAs / InAsSb superlattice detector;

[0061] The N-type doping layer and / or the P-type doping layer of the voltage-stabilizing PN junction is at least one of an InAs / AlSb superlattice layer, an InAs / GaSb superlattice layer, an InAs / GaSb / AlSb / GaSb superlattice layer and an InAsSb layer.

[0062] Please refer to Figure 5, which includes, from top to bottom, an N-type InAs / AlSb superlattice doped layer 20K, a weakly doped P-type InAs / AlSb superlattice layer 20L, a weakly doped P-type InAs / GaSb superlattice layer 20M, a P-type InAsSb doped layer 20N and an N-type InAsSb doped layer 20O.

[0063] The specific system material types when the photovoltaic infrared detector 20 is a short-wave detector, a medium-wave detector and a long-wave detector are given above. The above-mentioned various material systems are corresponding preferred materials. Of course, other system materials can also be selected according to actual conditions, and the present invention is not limited here.

[0064] The photovoltaic infrared detector 20 provided by the present invention comprises a stacked N-type doping layer and a P-type doping layer; the N-type doping layer and the P-type doping layer form a photoelectric detection PN junction 21 and a voltage-stabilizing PN junction 22 in opposite directions; the photovoltaic infrared detector 20 operates under a bias voltage, and the forward conduction direction of the voltage-stabilizing PN junction 22 is the same as the bias voltage direction. The photovoltaic infrared detector 20 of the present invention can weaken the voltage fluctuation on the photoelectric detection PN junction 21 when the external bias voltage fluctuates, because the voltage-stabilizing PN junction 22 has a voltage-dividing effect, thereby reducing the output signal fluctuation caused by the dark current with the bias voltage fluctuation, reducing noise, and improving the detection resolution of the photovoltaic infrared detector 20. In addition, under illumination conditions, the number of carriers in the photoelectric detection PN junction 21 increases, that is, the conductivity of the photoelectric detection PN junction 21 increases, and the corresponding resistance decreases, which will cause the voltage-dividing on the voltage-stabilizing PN junction 22 to increase, and the forward resistance corresponding to the voltage-stabilizing PN junction 22 will also be greatly reduced, so the effect of adding the voltage-stabilizing PN junction 22 on the light response is very small.

[0065] The present invention also provides an infrared detection device, the infrared detection device comprising a plurality of photovoltaic infrared detectors 20 as described in any one of the above;

[0066] A plurality of the photovoltaic infrared detectors 20 are arranged in an array.

[0067] The photovoltaic infrared detector 20 provided by the present invention comprises a stacked N-type doping layer and a P-type doping layer; the N-type doping layer and the P-type doping layer form a photoelectric detection PN junction and a voltage-stabilizing PN junction in opposite directions; the photovoltaic infrared detector 20 operates under a bias voltage, and the forward conduction direction of the voltage-stabilizing PN junction is the same as the bias voltage direction. The material energy gap corresponding to the voltage-stabilizing PN junction is greater than the material energy gap corresponding to the photoelectric detection PN junction. The photovoltaic infrared detector 20 of the present invention, when the external bias voltage fluctuates, can weaken the voltage fluctuation on the photoelectric detection PN junction due to the voltage-dividing effect of the voltage-stabilizing PN junction, thereby reducing the output signal fluctuation caused by the dark current with the bias voltage fluctuation, reducing noise, and improving the detection resolution of the photovoltaic infrared detector 20. In addition, under illumination conditions, the number of carriers in the photoelectric detection PN junction increases, that is, the conductivity of the photoelectric detection PN junction increases, and the corresponding resistance decreases, which will cause the voltage-dividing effect on the voltage-stabilizing PN junction to increase, and the forward resistance corresponding to the voltage-stabilizing PN junction will also be greatly reduced, so the effect of adding a voltage-stabilizing PN junction on the light response is very small.

[0068] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0069] It should be noted that, in this specification, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0070] The above is a detailed introduction to a photovoltaic infrared detector 20 and infrared detection equipment provided by the present invention. This article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A photovoltaic infrared detector, characterized in that: comprising a stacked N-type doped layer and a P-type doped layer; The N-type doping layer and the P-type doping layer form a photoelectric detection PN junction and a voltage stabilizing PN junction in opposite directions; The photovoltaic infrared detector operates under a bias voltage, and the forward conduction direction of the voltage-stabilizing PN junction is the same as the direction of the bias voltage.

2. The photovoltaic infrared detector according to claim 1, characterized in that: The material energy gap corresponding to the voltage-stabilizing PN junction is greater than the material energy gap corresponding to the photoelectric detection PN junction.

3. The photovoltaic infrared detector according to claim 2, characterized in that: At least one of the doping layers included in the voltage-stabilizing PN junction is arranged on the non-absorption layer of the photovoltaic infrared detector.

4. The photovoltaic infrared detector according to claim 3, characterized in that: The photovoltaic infrared detector is a short-wave InGaAs detector; The N-type doping layer and / or the P-type doping layer of the voltage-stabilizing PN junction is at least one of an InP doping layer, an InAlAs doping layer and an InAsP doping layer; The voltage-stabilizing PN junction is arranged in the contact layer of the photovoltaic infrared detector.

5. The photovoltaic infrared detector according to claim 3, characterized in that: The photovoltaic infrared detector is a medium-wave InAs / InAsSb superlattice detector or a medium-wave InAsSb bulk material detector; The N-type doped layer and / or the P-type doped layer of the voltage-stabilizing PN junction is at least one of an InAs / InAsSb superlattice layer and an InAsSb layer; The voltage-stabilizing PN junction is arranged in the contact layer of the photovoltaic infrared detector.

6. The photovoltaic infrared detector according to claim 3, characterized in that: The photovoltaic infrared detector is a long-wave InAs / GaSb superlattice detector or an InAs / InAsSb superlattice detector; The N-type doping layer and / or the P-type doping layer of the voltage-stabilizing PN junction is at least one of an InAs / AlSb superlattice layer, an InAs / GaSb superlattice layer, an InAs / GaSb / AlSb / GaSb superlattice layer and an InAsSb layer.

7. The photovoltaic infrared detector according to claim 1, characterized in that: The photovoltaic infrared detector includes two P-type doping layers and one N-type doping layer; The N-type doping layer is arranged between the two P-type doping layers.

8. The photovoltaic infrared detector according to claim 7, characterized in that: The photovoltaic infrared detector also includes an N-type mother layer; One of the two P-type doped layers is a P-type doped layer diffused in the N-type mother layer.

9. The photovoltaic infrared detector according to claim 1, characterized in that: The photovoltaic infrared detector includes two N-type doped layers and one P-type doped layer; The P-type doping layer is arranged between the two N-type doping layers.

10. An infrared detection device, characterized in that: The infrared detection device comprises a plurality of photovoltaic infrared detectors as claimed in any one of claims 1 to 9; A plurality of the photovoltaic infrared detectors are arranged in an array.

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