Preparation method of planar side-collection structure InGaAs infrared detector chip

Abstract

The invention discloses a preparation method of a planar lateral collection structure InGaAs infrared detector chip. The method comprises the following steps: 1, performing epitaxial material cleaning; 2, decomposing a silicon nitride diffusion mask; 3, performing first photoetching; 4, arranging a diffusion window; 5, peeling a photoresist; 6, performing closed-tube diffusion; 7, opening a tube to take a sheet out; 8, performing second photoetching; 9, growing a P electrode; 10, peeling a photoresist; 11, decomposing a silicon dioxide reflection reducing coating; 12, performing P electrode annealing; 13, performing third photoetching; 14, opening a P electrode hole; 15, peeling a photoresist; 16, performing fourth photoetching; 17, thickening the P electrode; 18, peeling a photoresist; 19, performing back-surface polishing; 20, growing an N electrode; and 21, performing scribing. The chip prepared by use of the preparation method reduces the diffusion area of a photosensitive element, can effectively reduce thermal damage caused by diffusion, reduces surface compounding through introduction of a double-layer passivation technology, prolongs the life of a minority of carriers, reduces dark currents and the blind pixel rate of a device, and improves the detectability of a detector.

Description

technical field [0001] The invention relates to an infrared detector chip, in particular to a method for preparing an indium gallium arsenide infrared detector chip with a positively irradiated plane type and a lateral collection structure. Background technique [0002] InGaAs short-wave infrared detectors can work at room temperature and have broad application prospects in civil, military and aerospace fields. At present, PIN InGaAs detectors are mainly divided into two types: planar type and mesa type. Due to the difficulty of passivation on the side of the mesa device, the reliability of the device is reduced and the dark current is large, which limits the improvement of the detection rate of the device to a large extent. Planar detectors are the mainstream structure of InGaAs detectors. The PN junction region of the device is mainly prepared by Zn high-temperature diffusion in n-InP / i-InGaAs / n-InP epitaxial materials, which has the advantages of easy passivation, dark c...

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Problems solved by technology

However, this preparation process makes the surface of the device prone to thermal damage due to diffusion during the high-temperature diffusion process. In addition, the out-diffusion of Zn and P elements in the subsequent heat treatment process increases the defect density in the epitaxial layer, resulting in the deterioration of the PN junction. Poor, which largely limits the further reduction of detector dark current and blind cell rate

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