Preparation method of avalanche photodetector

Abstract

The invention discloses a preparation method of an avalanche photodetector. The preparation method comprises the following steps: firstly, sequentially growing a p-type InP buffer layer, an In < 0.53 > Ga < 0.47 > As absorption layer, an In < 1-x-y > Al < x > Ga < y > As bandwidth gradient layer, a p-type In < 0.52 > Al < 0.48 > As charge control layer, an In < 0.52 > Al < 0.48 > As multiplication layer, an In < x > Ga < 1-x > As < y > P < 1-y > corrosion cut-off layer and a p-type InP cover layer on a p-type InP substrate; then corroding the p-type InP cover layer, wherein the corroded region comprises a central region and one or more annular regions surrounding the central region; carrying out secondary epitaxy on n-type InP in the corroded region to form an n-type InP central collector region and an n-type InP electric field protection ring; then depositing a SiO2 layer, and etching off SiO2 in a partial region to form a circle of annular SiO2 isolation layer; depositing an optical anti-reflection film and forming a metal contact window on the optical anti-reflection film above the central collector region; then constructing an upper electrode, wherein the upper electrode is in contact with the central collector region through the metal contact window; and finally, preparing a back electrode on the back surface of the InP substrate.

Description

technical field [0001] The invention belongs to the technical field of photodetectors, and in particular relates to a preparation method of an avalanche photodetector. Background technique [0002] The working principle of the avalanche photodetector is to use the p-i-n junction under a relatively high reverse bias electric field. Photons are incident on the i region to make electrons transition from the valence band to the conduction band, forming electron-hole pairs. Under the action of a strong electric field, the electrons- The hole pairs get accelerated, collide with other atoms, create additional electron-hole pairs and keep on happening. Since the incidence of fewer photons or even a single photon can trigger the avalanche multiplication process and cause changes in the macroscopic current, the avalanche photodetector has extremely high sensitivity and detection efficiency, and has a very high potential in the field of weak light detection or even single photon detect...

AI Technical Summary

Problems solved by technology

However, Zn diffusion is a difficult and highly variable process to precisely control

Instability of the Zn diffusion process causes detector inconsistencies while reducing yield in production

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