Plane-structure InGaAs array infrared detector

Abstract

The invention discloses a novel plane-structure InGaAs array infrared detector. The structural design of the infrared detector is as follows: a shallow isolation groove is formed around an array photosensitive surface on an NIN-type epitaxial wafer by etching; a PN junction area of the photosensitive surface is formed by closed tube diffusion, and a guard ring integrated with the shallow isolation groove is formed; and guard ring electrodes and annular covering electrodes are formed by thickening Cr / Au. The novel plane-structure InGaAs array infrared detector has the advantages that the shallow isolation groove and the guard ring with the integrated design can effectively inhibit cross talk between adjacent photosensitive surfaces of an array device and enlargement of the photosensitive surfaces, and the enlargement of the photosensitive surfaces can be further inhibited and the photosensitive surfaces can be accurately defined if the infrared detector is aided with small diffusion holes and the annular covering electrodes. In the plane extension wavelength InGaAs array device, the shallow isolation groove can also help effectively inhibit drain current between P electrodes of adjacent photosensitive surfaces caused by lattice mismatching of materials.

Description

technical field [0001] The photodetector technology involved in the present invention specifically refers to a planar structure indium gallium arsenide array infrared detector. Background technique [0002] At present, PIN InGaAs detectors are mainly divided into two types: planar type and mesa type. The mesa-type InGaAs detector is to etch the P-InP / InGaAs in the epitaxial material into a mesa, which fundamentally isolates the adjacent photosensitive surfaces. The detector of this structure has the advantages of simple preparation process and adjacent photosensitive surfaces. It has the advantages of low crosstalk and easy definition of the photosensitive surface, but the exposed side of the mesa detector brings great difficulties to the passivation of the device, which will reduce the reliability of the device and increase the noise. Limiting the improvement of device detection rate. As the mainstream structure of indium gallium arsenide detectors, planar indium gallium ...

AI Technical Summary

Problems solved by technology

But it also has some unavoidable disadvantages: the expansion of the photosensitive surface makes it difficult to define the photosensitive surface, and the crosstalk between adjacent photosensitive surfaces is large, etc., which limit the improvement of the performance of InGaAs detectors.

At present, the general method is to use small diffusion holes to control the expansion of the photosensitive surface, use ring electrodes to define the photosensitive surface, and introduce guard rings to reduce device crosstalk. However, these methods are generally used alone and cannot fundamentally To solve the shortcomings of planar devices

In addition, for the extended-wavelength InGaAs array device with planar structure, due to the lattice mismatch of materials, there is a large leakage current between the P electrodes on the adjacent photosensitive surface, and the existing planar structure cannot solve this problem.

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