Avalanche photodiode and manufacturing method thereof

Abstract

The invention discloses an avalanche photodiode and a manufacturing method thereof, and relates to the technical field of photodiodes. The avalanche photodiode comprises a bottom layer and a top layer, wherein the bottom layer includes a substrate, a buffer layer and a light absorption layer, and the lower surface of the substrate is provided with a cathode; the top layer is arranged above the bottom layer and includes an avalanche gain layer and a zinc diffusion layer; the zinc diffusion layer includes a non-diffusion region and a zinc diffusion region, the non-diffusion region and part of the zinc diffusion region are etched, the part, which is not etched, of the zinc diffusion region is a photosensitive region, and the etched part of the zinc diffusion region is an annular groove; an insulating layer is evaporated on the non-diffusion region and part of the annular groove, and an annular anode is evaporated on the annular groove which is not evaporated with the insulating layer andthe insulating layer; and the annular anode, the insulating layer and the cathode form an MIS structure. The avalanche photodiode of the invention can generate an anode capacitance effect, change theelectric field distribution at the edge of a p-type doping region below the anode, reduces the curvature at the edge of a depletion region, reduce the edge electric field intensity and thus suppress the edge pre-breakdown.

Description

technical field [0001] The invention relates to the technical field of photodiodes, in particular to an avalanche photodiode and a manufacturing method thereof. Background technique [0002] When manufacturing planar avalanche photodiodes (Avalanche Photodiodes: APD), especially APDs based on III-V materials, the size of the photosensitive surface of the device is determined by the zinc diffusion window, and the edge area of ​​the diffusion window is caused by the curvature effect. The electric field intensity in the area is higher than that in the central area of ​​the photosensitive surface, resulting in a lower gain in the central part of the photosensitive surface of the device, that is, the gain available in practical applications is lower, and edge pre-breakdown is prone to occur, making it impossible to use normally. [0003] The existing APD methods for suppressing edge pre-breakdown mainly include: 1. Perform epitaxial regrowth after etching the area around the char...

AI Technical Summary

Problems solved by technology

Although the above two methods can suppress edge breakdown, due to the complex process and difficult control, it is easy to cause problems such as increased diode manufacturing costs, reduced device yield, and reduced device consistency.

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