Novel structure of long-wave infrared detector based on InAs-AlSb barrier

Abstract

The invention discloses a novel structure of a long-wave infrared detector based on an InAs-AlSb barrier, the whole structure of the novel structure is a p pi Bn structure, an InAs / GaSb superlattice structure is used as a top contact layer and an absorption layer, and an InAs / AlSb superlattice is used as a barrier layer and a bottom contact layer. The device structure provided by the invention is relatively low in dark current density at 77K. The InAs / AlSb superlattice barrier layer is added to a traditional pin structure device, the dark current level is effectively restrained, and the working performance of the device is guaranteed.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a novel structure of a long-wave infrared detector based on an InAs-AlSb barrier. Background Art

[0002] Type-II superlattice long-wave infrared detectors are an infrared detection technology based on semiconductor heterostructures, widely used in high-end detection fields such as military reconnaissance and environmental monitoring. This technology utilizes the energy band differences of heterogeneous materials to form a "type-II superlattice." Compared to traditional single-material infrared detectors, type-II superlattice long-wave infrared detectors offer unique advantages in handling detection tasks in low-temperature environments. Type-II superlattice materials can precisely control the detector's response wavelength and performance parameters by adjusting the material's band gap and layer thickness, thereby achieving high-sensitivity detection in low-temperature, high-noise environments.

[0003] However, the currently available Type II superlattice long-wave infrared detectors still face several technical challenges. Their dark current remains a key factor affecting their performance. Excessive dark current can lead to a decrease in the signal-to-noise ratio, thereby reducing the detector's sensitivity. Therefore, optimizing the superlattice structure and reducing the detector's dark current remain hot research topics, as well as challenges. Summary of the Invention

[0004] The present invention provides a novel structure of a long-wave infrared detector based on an InAs-AlSb barrier to solve the technical problems mentioned in the background technology.

[0005] A novel structure of a long-wave infrared detector based on an InAs-AlSb barrier has an overall structure of a pπBn structure, an InAs / GaSb superlattice structure is used as the top contact layer and absorption layer, and an InAs / AlSb superlattice is used as the barrier layer and bottom contact layer.

[0006] As a further technical solution of the present invention, the top contact layer and the absorption layer are p-type doped, and the barrier layer and the bottom contact layer are n-type doped; wherein the absorption layer and the barrier layer are weakly doped, and the doping concentration is 1×10 16 cm -3 and 1×10 15 cm -3 The top and bottom contact layers are heavily doped, with a doping concentration of 1×10 18 cm -3 .

[0007] As a further technical solution of the present invention, a 0.5 μm InAs / AlSb superlattice is grown as a bottom contact layer, a 0.5 μm InAs / AlSb superlattice is grown on the bottom contact layer as a barrier layer, a 3 μm InAs / GaSb superlattice is grown on the barrier layer as an absorption layer, and a 0.3 μm InAs / GaSb superlattice is grown on the absorption layer as a top contact layer.

[0008] Beneficial effects achieved by the present invention:

[0009] The device structure provided by the present invention has a low dark current density at 77 K. The present invention adds an InAs / AlSb superlattice barrier layer to the traditional pin structure device, effectively suppressing the dark current level and ensuring the working performance of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 Schematic diagram of a new structure of a long-wave infrared detector based on InAs-AlSb barrier.

[0011] Figure 2 This is the energy band diagram of the pπMn device structure.

[0012] Figure 3 Dark current density diagram (left) and electric field intensity diagram (right) of the pπMn device at 77K.

[0013] Reference numerals: 1 - top contact layer, 2 - absorption layer, 3 - barrier layer, 4 - bottom contact layer. DETAILED DESCRIPTION

[0014] The technical solution of the present invention is described in detail below with reference to the accompanying drawings.

[0015] See also Figure 1 The embodiment of the present invention provides a new structure of a long-wave infrared detector based on an InAs-AlSb barrier, whose overall structure is a pπBn structure, using an InAs / GaSb superlattice structure as the top contact layer 1 and the absorption layer 2, and using an InAs / AlSb superlattice as the barrier layer 3 and the bottom contact layer 4.

[0016] In this embodiment, the top contact layer 1 and the absorption layer 2 are p-type doped, and the barrier layer 3 and the bottom contact layer 4 are n-type doped; the absorption layer 2 and the barrier layer 3 are weakly doped, with doping concentrations of 1×10 16 cm -3 and 1×10 15 cm -3 The top contact layer 1 and the bottom contact layer 4 are heavily doped, with a doping concentration of 1×10 18 cm -3 .

[0017] In this embodiment, a 0.5 μm InAs / AlSb superlattice is grown as the bottom contact layer 4, a 0.5 μm InAs / AlSb superlattice is grown on the bottom contact layer 4 as the barrier layer 3, a 3 μm InAs / GaSb superlattice is grown on the barrier layer 3 as the absorption layer 2, and a 0.3 μm InAs / GaSb superlattice is grown on the absorption layer 2 as the top contact layer 1; the InAs / GaSb material of the absorption layer 2 can effectively control its bandgap by controlling the ratio of InAs and GaSb, and the wavelength range can cover the long-wave range; the InAs / AlSb material can effectively control its bandgap by controlling the thickness of InAs and AlSb, so that the bandgap of the barrier layer 3 is wide and can hinder the movement of majority carriers.

[0018] Figure 2 This is the energy band diagram of the pπBn device structure. The absorber and barrier layer materials designed in this invention have essentially identical affinities, resulting in a minimal offset of the energy band from the conduction band. Furthermore, due to the relatively small band gap of the absorber layer material and the relatively large band gap of the barrier layer material, a significant offset is generated in the valence band, thereby blocking the flow of carrier holes and, to a certain extent, suppressing dark current.

[0019] Theoretical calculations show that at 77K and a bias voltage of -100mV, the dark current density of the structure is 4.5×10 -4 A / cm 2 This is due to the introduction of the InAs / AlSb barrier structure, which makes most of the depletion layer fall on the wide-bandgap barrier layer, reducing the probability of generation-recombination and thus reducing the dark current level.

[0020] It should be noted that, in this document, the term "comprises" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article, or apparatus that includes a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0021] The above are only preferred embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A novel structure of a long-wave infrared detector based on an InAs-AlSb barrier, characterized in that: Its overall structure is a pπBn structure, using an InAs / GaSb superlattice structure as a top contact layer and an absorption layer, and an InAs / AlSb superlattice as a barrier layer and a bottom contact layer.

2. The novel structure of the long-wave infrared detector based on the InAs-AlSb barrier according to claim 1 is characterized in that: The top contact layer and the absorption layer are p-type doped, and the barrier layer and the bottom contact layer are n-type doped; wherein the absorption layer and the barrier layer are weakly doped, and the doping concentration is 1×10 16 cm -3 and 1×10 15 cm -3 The top and bottom contact layers are heavily doped, with a doping concentration of 1×10 18 cm -3 .

3. The novel structure of the long-wave infrared detector based on the InAs-AlSb barrier according to claim 1 is characterized in that: A 0.5 μm InAs / AlSb superlattice is grown as the bottom contact layer, a 0.5 μm InAs / AlSb superlattice is grown on the bottom contact layer as the barrier layer, a 3 μm InAs / GaSb superlattice is grown on the barrier layer as the absorption layer, and a 0.3 μm InAs / GaSb superlattice is grown on the absorption layer as the top contact layer.

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