Growth method of surface passivation layer of mesa detector

Abstract

The invention discloses a growth method of a surface passivation layer of a mesa detector. The growth method comprises the following steps of: forming a SiO2 passivation film on the surface of the mesa structure of a wafer by using a plasma chemical vapor deposition process in a low-temperature environment; coating a polyimide film on the SiO2 passivation film and carrying out gradient curing to densify the polyimide film; spin-coating a photoresist on the polyimide film to form a photoresist layer, and forming an exposure region on the photoresist layer; developing the photoresist layer of the exposure region, etching the polyimide film of the exposure region, and then removing the photoresist layer; performing imidization treatment on the polyimide film so that the polyimide film is fixed to the surface of the SiO2 passivation film; and etching the exposed SiO2 passivation film to set apart an electrode position. The growth method disclosed by the invention can be used for improving the passivation quality of the mesa detector, effectively reducing the surface leakage current of a device, preventing the device from premature breakdown, and improving the reliability of the device.

Description

technical field [0001] The invention relates to the field of semiconductor surface passivation, in particular to a method for growing a mesa detector surface passivation layer. Background technique [0002] The surface state is one of the key factors affecting the performance of the detector. In order to improve the performance of the device, it is necessary to reduce the surface state. Surface passivation is an effective means to suppress or reduce surface states. Compared with planar devices, the mesa detector has a larger surface area, and the PN junction around the mesa is exposed, which makes it more difficult to passivate the device surface, especially the avalanche detector (working in a high bias state). Therefore, how to improve the quality of surface passivation is the focus of attention in the development and production of mesa detectors, and is the key process of mesa detectors. If the surface passivation effect is not good, the surface of mesa detectors will be...

AI Technical Summary

Problems solved by technology

with monolayer SiO 2 film passivation will cause the SiO 2 The passivation layer is thinner, which leads to SiO 2 The probability of pinholes in the passivation layer increases, which can easily cause passivation to fail

Although polyimide has excellent adhesion and flow properties, when the polyimide film is directly used to passivate the mesa, the solvent is easy to volatilize when the polyimide is imidized, resulting in more pores at the interface, so the passivation The chemical effect is not ideal

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