A detector with low surface leakage current and its manufacturing method

Abstract

The invention provides a detector with low surface leakage current, which comprises an InP substrate, on which an isolation platform and a P platform formed by etching are sequentially grown. A first passivation layer and a second passivation layer are grown sequentially on the upper surfaces of the substrate, the isolation platform and the P platform, and the side surfaces of the isolation platform and the P platform. The upper surface of the isolation platform is provided with an n-type contact metal ring passing through the first passivation layer and the second passivation layer, and the upper surface of the P platform is provided with an n-type contact metal ring passing through the first passivation layer and the second passivation layer. The p-type contact metal ring of the second passivation layer. The present invention uses a composite passivation layer (the composite passivation layer is semi-insulating InP or InAlAs and a dielectric film passivation layer from bottom to top) to replace the traditional dielectric film passivation layer to passivate the detector, reducing the interface between the passivation layer and the semiconductor The defects and interface states between them are beneficial to reduce the leakage current of the device.

Description

Technical field [0001] The present invention belongs to the field of chip manufacturing, and more particularly to a detector of a low surface leakage current and a method of fabricating it. Background technique [0002] Existing table-type PD (photodiode detector), table-type APD (avalanche photodiode detector) After the surface etching process is completed, there is a large number of suspension keys and surface defects, these suspensions and defects. It will increase the surface leakage current of the device. Leakage current is one of the most important parameters characterized by characterizing detector performance, and its size directly affects the performance of the device. The desktop passivation process can reduce the role of surface leakage current. [0003] Conventional counterturization is mainly in a deposition of dielectric membranes in a countertop (SiO 2 Or SINX is implemented. Taking the media membrane passivation layer in the INP base detector table as an example, ...

AI Technical Summary

Problems solved by technology

Although it can still play a passivation role, SiO 2 or SiN x There will still be a large number of dangling bonds between the dielectric film and the side wall of the PD mesa

In addition, the process of depositing a dielectric film on the sidewall of the mesa by plasma enhanced chemical vapor deposition (PECVD) will also cause damage to the mesa and its sidewall

[0004] Therefore, detectors manufactured by conventional passivation methods still face the problems of surface defects and dangling bonds, and the surface characteristics need to be further improved

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