Novel medium-wave high-temperature infrared detector

Abstract

The invention discloses a novel medium-wave high-temperature infrared detector, the overall structure of the novel medium-wave high-temperature infrared detector is an nBp structure, an InAs / InAsSb superlattice structure is adopted as an absorption layer, an AlAsSb / InAsSb superlattice structure is adopted as a barrier layer, an InAs / InAsSb superlattice structure is adopted as a contact layer, the contact layer comprises an upper contact layer and a lower contact layer, wherein the barrier layer and the absorption layer are arranged between the upper contact layer and the lower contact layer, the barrier layer is arranged between the absorption layer and the upper contact layer, and a GaSb buffer layer is arranged between the lower contact layer and the GaSb substrate. The structure is optimized, so that the working temperature of the device can be improved and the collection rate of photon-generated carriers can be improved under the condition that dark current is kept or even under a lower condition, and the working performance of the infrared detector can be effectively ensured and improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a novel mid-wave high-temperature infrared detector. Background Technology

[0002] Mid-wave infrared detection technology has crucial applications in both civilian and defense sectors, such as environmental monitoring, ground disaster detection, gas detection, critical equipment, and reconnaissance. Existing cooled mid-wave infrared detectors are large, power-consuming, and expensive, limiting their application in certain scenarios. Antimony compound InAs / InAsSb type-II superlattice infrared detectors offer better uniformity, lower cost, and superior high-temperature performance compared to HgCdTe infrared detectors. Mid-wave infrared type-II superlattice detector chips, with their lower cost, are a key future development direction. However, current products can only operate at 77K, typically requiring the use of Stirling coolers, which offer forced cooling but are more expensive, larger, heavier, and more power-consuming. This makes it difficult to effectively combine with the smaller, lower-cost, and higher-performance solid-state cooling. Therefore, overcoming the dark current suppression challenge of mid-wave infrared detectors at high operating temperatures and developing high-performance mid-wave infrared detectors is urgently needed. Summary of the Invention

[0003] This invention provides a novel mid-wave high-temperature infrared detector to solve the technical problems mentioned in the background art.

[0004] A novel mid-wave high-temperature infrared detector has an overall nBp structure, employing an InAs / InAsSb superlattice structure as the absorption layer, an AlAsSb / InAsSb superlattice structure as the barrier layer, and an InAs / InAsSb superlattice structure as the contact layer. The contact layer includes an upper contact layer and a lower contact layer, with the barrier layer and absorption layer disposed between the upper and lower contact layers, and the barrier layer located between the absorption layer and the upper contact layer. A GaSb buffer layer is disposed between the lower contact layer and the GaSb substrate.

[0005] As a further technical solution of the present invention, a 500 nm GaSb buffer layer is grown on a GaSb substrate, which is p-type doped with a doping concentration of 1 × 10⁻⁶. 18 cm -3 .

[0006] As a further technical solution of the present invention, a 1000 nm InAs / InAsSb lower contact layer is grown on the GaSb buffer layer, p-type doped, with a doping concentration of 5 × 10⁻⁶. 17 cm -3 .

[0007] As a further technical solution of the present invention, a 4000 nm absorption layer is grown on the lower contact layer, which is n-type doped with a doping concentration of 5 × 10⁻⁶. 14 cm -3 The superlattice structure of the absorption layer is 12ML InAs / 3ML InAsSb.

[0008] As a further technical solution of the present invention, a 900nm superlattice structure is grown on the absorption layer as a barrier layer, and n-type doped with a doping concentration of 5×10⁻⁶. 14 cm -3 The superlattice structure of the barrier layer is 3ML AlAsSb / 7ML InAsSb.

[0009] As a further technical solution of the present invention, a 500 nm InAs / InAsSb upper contact layer is grown on the barrier layer, p-type doped, with a doping concentration of 1×10⁻⁶. 18 cm -3 .

[0010] As a further technical solution of the present invention, the working temperature is 150K and the working bias voltage is -0.3V.

[0011] The beneficial effects achieved by this invention are as follows:

[0012] This invention primarily uses Ga-free material systems in its material selection. By optimizing the structure, this invention can ensure that the dark current is maintained or even lower, improve the operating temperature of the device, enhance the collection rate of photogenerated carriers, and effectively guarantee and improve the working performance of the infrared detector. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of a novel mid-wave high-temperature infrared detector.

[0014] Figure 2 The figure shows the theoretical calculation results of dark current for the nBp device structure under three conditions.

[0015] Figure 3 This is a diagram showing the proportion of the electric field falling on the barrier layer in three different scenarios.

[0016] Figure label annotations: 1-upper contact layer, 2-barrier layer, 3-absorption layer, 4-lower contact layer, 5-GaSb buffer layer, 6-GaSb substrate. Detailed Implementation

[0017] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings.

[0018] This invention ensures a smooth bandgap transition by optimizing the superlattice material composition of the absorption layer and barrier layer. Simultaneously, the proportion of the depletion layer in the barrier layer explains why the dark current is low in number 3 among the three different designations.

[0019] Please see Figure 1 This invention provides a novel mid-wave high-temperature infrared detector with an overall nBp structure. The device structure uses an InAs / InAsSb superlattice structure as the absorption layer 3, an AlAsSb / InAsSb superlattice structure as the barrier layer 2, and an InAs / InAsSb superlattice structure as the contact layer. The contact layer includes an upper contact layer 1 and a lower contact layer 4. The barrier layer 2 and the absorption layer 3 are disposed between the upper contact layer 1 and the lower contact layer 4, and the barrier layer 2 is located between the absorption layer 3 and the upper contact layer 1. A GaSb buffer layer 5 is disposed between the lower contact layer 4 and the GaSb substrate 6.

[0020] In this embodiment, a 500 nm GaSb buffer layer 5 is grown on the GaSb substrate 6, which is p-type doped with a doping concentration of 1 × 10⁻⁶. 18 cm -3 .

[0021] In this embodiment, a 1000nm InAs / InAsSb lower contact layer 4 is grown on the GaSb buffer layer 5, with p-type doping and a doping concentration of 5×10⁻⁶. 17 cm -3 .

[0022] In this embodiment, a 4000 nm absorption layer 3 is grown on the lower contact layer 4, and is n-type doped with a doping concentration of 5 × 10⁻⁶. 14 cm -3 The superlattice structure of the absorption layer 3 is 12ML InAs / 3ML InAsSb.

[0023] In this embodiment, a 900 nm superlattice structure is grown on the absorber layer 3 as the barrier layer 2, and is n-type doped with a doping concentration of 5 × 10⁻⁶. 14 cm -3 The superlattice structure of the barrier layer 2 is 3ML AlAsSb / 7ML InAsSb. The band gap of the AlAsSb / InAsSb material can be effectively controlled by controlling the number of periods of AlAsSb and InAsSb and the content of Sb composition, so as to ensure that its band gap is large enough to impede the flow of majority carriers.

[0024] In this embodiment, a 500nm InAs / InAsSb upper contact layer 1 is grown on the barrier layer 2, with p-type doping and a doping concentration of 1×10⁻⁶. 18 cm -3Using an InAs / InAsSb superlattice structure as the contact layer, a certain bias voltage is required to collect minority carriers while ensuring lattice matching.

[0025] In this embodiment, the operating temperature is 150K and the operating bias voltage is -0.3V. The electrode can be installed between the lower contact layer 4 and the GaSb buffer layer 5, and above the upper contact layer 1.

[0026] Figure 2 These are the theoretical calculation results of the dark current of the nBp device structure under three conditions, where the thickness and doping concentration of the absorption region in case number 3 are 4 μm and 5 × 10⁻⁶, respectively. 14 cm -3 The barrier region thickness and doping concentration are 0.9 μm and 5 × 10⁻⁶, respectively. 14 cm -3 The thickness and doping concentration of absorption region No. 2 are 4 μm and 5 × 10⁻⁶, respectively. 14 cm -3 The barrier region thickness and doping concentration are 0.3 μm and 0, respectively, while the absorption region numbered 3 has a thickness and doping concentration of 3.5 μm and 5 × 10⁻⁶, respectively. 15 cm -3 The barrier region thickness and doping concentration are 0.9 μm and 5 × 10⁻⁶, respectively. 14 cm -3 All three devices listed above operate at 150K with a bias voltage of -0.3V. It can be clearly seen that device number 3—when the thicknesses of the absorption and barrier regions are 4μm and 0.9μm respectively, and the doping concentrations are 5×10⁻⁶... 14 cm -3 and 5×10 14 cm -3 At that time, the dark current is at its lowest.

[0027] To explain this situation, we compare the three types of electric field diagrams, such as... Figure 3 As shown in (a), (b), and (c), it can be clearly seen that the depletion layer accounts for 85%, 56%, and 20% of the barrier layer, respectively. This indicates that when the thicknesses of the absorption layer and the barrier layer are 4 μm and 0.9 μm, respectively, and the doping concentrations are 5 × 10⁻⁶, the depletion layer accounts for 85%, 56%, and 20%, respectively. 14 cm -3 and 5×10 14 cm -3 At this time, the depletion layer falls more heavily in the barrier region. Since the barrier region is composed of a wide-bandgap superlattice material, the generation-recombination current in the barrier region is very small. However, the generation-recombination current is a crucial component of the device's dark current during high-temperature operation. Therefore, number 3... Figure 2 It exhibits a low dark current level, which provides a way for high-temperature operating devices to maintain performance.

[0028] It should be noted that, in this document, the term "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0029] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A novel mid-wave high-temperature infrared detector, characterized in that, Its overall structure is an nBp structure, using an InAs / InAsSb superlattice structure as the absorption layer, an AlAsSb / InAsSb superlattice structure as the barrier layer, and an InAs / InAsSb superlattice structure as the contact layer. The contact layer includes an upper contact layer and a lower contact layer. The barrier layer and the absorption layer are disposed between the upper contact layer and the lower contact layer, and the barrier layer is located between the absorption layer and the upper contact layer. A GaSb buffer layer is disposed between the lower contact layer and the GaSb substrate.

2. The novel mid-wave high-temperature infrared detector according to claim 1, characterized in that, A 500 nm GaSb buffer layer, p-type doped, is grown on a GaSb substrate with a doping concentration of 1 × 10⁻⁶. 18 cm -3 .

3. The novel mid-wave high-temperature infrared detector according to claim 1, characterized in that, A 1000 nm InAs / InAsSb lower contact layer, p-type doped, was grown on the GaSb buffer layer with a doping concentration of 5 × 10⁻⁶. 17 cm -3 .

4. The novel mid-wave high-temperature infrared detector according to claim 1, characterized in that, A 4000 nm absorption layer, n-type doped, is grown on the lower contact layer with a doping concentration of 5 × 10⁻⁶. 14 cm -3 The superlattice structure of the absorption layer is 12MLInAs / 3MLInAsSb.

5. A novel mid-wave high-temperature infrared detector according to claim 1, characterized in that, A 900 nm superlattice structure was grown on the absorber layer as a barrier layer, and it was n-type doped with a doping concentration of 5 × 10⁻⁶. 14 cm -3 The superlattice structure of the barrier layer is 3ML AlAsSb / 7ML InAsSb.

6. A novel mid-wave high-temperature infrared detector according to claim 1, characterized in that, A 500 nm InAs / InAsSb upper contact layer, p-type doped, was grown on the barrier layer with a doping concentration of 1 × 10⁻⁶. 18 cm -3 .

7. A novel mid-wave high-temperature infrared detector according to claim 1, characterized in that, All tests were conducted at a working temperature of 150K and a working bias voltage of -0.3V.

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