Microstructure enhanced absorption photosensitive devices

摘要

Techniques for enhancing the absorption of photons in semiconductors with the use of microstructures are described. The microstructures, such as holes, effectively increase the absorption of the photons. Using microstructures for absorption enhancement for silicon photodiodes and silicon avalanche photodiodes can result in bandwidths in excess of 10 Gb/s at photons with wavelengths of 850 nm, and with quantum efficiencies of approximately 90% or more. Their thickness dimensions allow them to be conveniently integrated on the same Si chip with CMOS, BiCMOS, and other electronics, with resulting packaging benefits and reduced capacitance and thus higher speeds.

主权项

1. An integrated detector/processor circuit for data communication comprising both a photodetector with microstructure-enhanced photoabsorption and an electronic processor formed into a single semiconductor chip, comprising:
a photodetector formed on a semiconductor substrate and comprising a photon absorbing region configured to absorb photons from an optical source signal modulated for data communication and provide an output electrical signal corresponding thereto; said photon absorbing region comprising an I-region that is between an N-region and a P-region and comprises a substantially continuous layer interrupted by a plurality of holes extending in said I-region toward said substrate and configured to concurrently receive the same source signal at a plural number of the holes; an electronic processor also formed on said semiconductor substrate and operatively associated with said photon absorbing region to receive therefrom and process said output electrical signal into a processed output, thereby forming a single semiconductor chip that receives the optical source signal and outputs the processed output; wherein said photon absorbing region and said electronic processor have respective thicknesses that are of the same order of magnitude; and a cathode region and an anode region operatively associated with said photon absorbing region and reverse biasing circuitry configured to apply a voltage between said cathode and anode regions such that said cathode region is driven to a more positive voltage than said anode region.