Low-noise semiconductor photodetectors

摘要

A photodetector is formed from a body of semiconductor material substantially surrounded by dielectric surfaces. A passivation process is applied to at least one surface to reduce the rate of carrier generation and recombination on that surface. Photocurrent is read out from at least one electrical contact, which is formed on a doped region whose surface lies entirely on a passivated surface. Unwanted leakage current from un-passivated surfaces is reduced through one of the following methods: (a) The un-passivated surface is separated from the photo-collecting contact by at least two junctions; (b) The un-passivated surface is doped to a very high level, at least equal to the conduction band or valence band density of states of the semiconductor; (c) An accumulation or inversion layer is formed on the un-passivated surface by the application of an electric field.

主权项

1. A method of detecting light, comprising:
using a semiconductor structure as a photodetector to detect incident light and generate an electrical signal representative of the detected incident light, the semiconductor structure comprising: a body of semiconductor material having a surface comprising a first portion and a second portion; a layer of a first dielectric material being configured to contact the first portion of the surface of the body of semiconductor material; a second dielectric material contacting the second portion of the surface of the body of semiconductor material and configured to passivate the second portion; wherein the body of semiconductor material comprises:
a first region doped to a first type of conductivity (p or n); anda second region peripherally around the first region doped to a second type of conductivity (n or p) opposite the first type of conductivity, the second region forming a p-n junction with the first region, the p-n junction intersecting the surface of the body of semiconductor material at the second portion of the surface; a plurality of ohmic contacts comprising a first ohmic contact to the first region and a second ohmic contact to the second region; and a highly doped semiconductor material substantially surrounding the layer of the first dielectric material, wherein the layer of the first dielectric material has a thickness configured to cause formation of an accumulation layer or an inversion layer at the first portion of the surface of the body of semiconductor material.