Relaxation GeSn infrared avalanche photodetector and manufacturing method thereof

Abstract

The invention relates to the technical field of semiconductor manufacturing, and particularly relates to a relaxation GeSn infrared avalanche photodetector and a manufacturing method thereof. The relaxation GeSn infrared avalanche photodetector comprises a substrate, a charge multiplication structure, a buffer layer and an absorption layer, wherein the charge multiplication structure, the buffer layer and the absorption layer are sequentially stacked on the substrate in the direction perpendicular to the substrate; the charge multiplication structure is made of a Si material; the absorption layer is made of a relaxation Ge<1-x>Snx material, and x is greater than 0 and less than 1; and the buffer layer is made of a Si<1-y>Gey material, y is larger than 0.2 and less than 0.8, and the defectdensity of the buffer layer is greater than a preset value so as to limit line dislocation propagation caused by lattice mismatch of the Si material and the relaxation Ge<1-x>Snx material. The relaxation GeSn infrared avalanche photodetector has large photocurrent amplification multiple and high sensitivity, the growth of a thick relaxation Ge buffer layer is avoided, and defect dislocation is limited in the buffer layer, so that the growth of a high-quality relaxation GeSn absorption layer is guaranteed.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a relaxation GeSn infrared avalanche photodetector and a manufacturing method thereof. Background technique [0002] Infrared photodetectors are widely used in communication, night vision, guidance, astronomical observation, and biomedicine. Compared with traditional III-V and II-V infrared photodetectors, IV infrared photodetectors are small in size, easy to integrate, low in cost and high in performance because of their manufacturing process compatibility with Si-based CMOS technology. and other potential advantages. Ge detectors based on Si substrates or SOI (Silicon On Insulator, silicon-on-insulator) substrates have been widely used in the fields of communication and sensing. However, when the wavelength of Ge material is greater than 1.55 μm, the absorption coefficient drops sharply, which makes Ge detectors unable to meet the applications of short-wav...

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Problems solved by technology

[0005] The invention provides a relaxation GeSn infrared avalanche photodetector and its manufacturing method, which is used to solve the problem of low sensitivity of the existing GeSn infrared photodetector

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