Transverse structure germanium/silicon heterojunction avalanche photoelectric detector and preparation method thereof

Abstract

The invention discloses a transverse structure germanium / silicon heterojunction avalanche photoelectric detector which is prepared on an SOI (Silicon-on-Insulator) substrate and has a double-tabletop structure. The transverse structure germanium / silicon heterojunction avalanche photoelectric detector comprises a substrate, a buried silicon oxide layer, a silicon tabletop area, silicon space areas, silicon contact areas, electrodes and a germanium epitaxial layer. The buried silicon oxide layer is formed on the silicon substrate. The silicon tabletop area is formed on the buried silicon oxide layer. The silicon space areas are formed on the buried silicon oxide layer at two sides of the silicon tabletop area. The silicon contact areas are formed on the buried silicon oxide layer outside the silicon space areas. The germanium epitaxial layer is formed on the silicon tabletop area. The electrodes are in ohmic contact with the silicon contact areas. The two electrodes are manufactured on a silicon layer. A germanium light absorbing layer is arranged above the silicon layer. A bias voltage which is applied to the two electrodes realize electric fields with different strengths in the light absorbing layer and the silicon layer. Light absorption is realized in the germanium and an avalanche multiplication process is realized in the silicon layer.

Description

technical field [0001] The invention relates to the field of semiconductor photodetectors, in particular to a lateral structure germanium / silicon heterojunction avalanche photodetector and a preparation method thereof. Background technique [0002] Avalanche photodetector is a photodetector with photoresponse multiplication function, which is especially suitable for detecting weak light signals. The basic principle is that light is absorbed by the detector to generate photogenerated carriers. Under the action of an electric field, electrons and holes gain energy and accelerate their movement. When the electric field is strong enough, electrons and holes are realized through collision ionization in motion. The multiplied, multiplied electrons and holes are collected by the electrodes, so as to obtain a multiplied and amplified response current. Although the multiplication of the photogenerated current is obtained, a large multiplication excess noise will be generated at the ...

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Problems solved by technology

[0003] However, the structure of this avalanche photodetector is complex, especially the requirements for doping control are very high, and the preparation is relatively difficult.

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