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. A microstructure-enhanced germanium-on-silicon avalanche photodetector for operation with an incident optical source signal at a wavelength range that includes 1550 nanometers, comprising:
a germanium P-layer; a germanium photon-absorbing I-layer under the germanium P-layer, said germanium photo-absorbing I-layer comprising a substantially continuous layer interrupted by a plurality of intentionally formed holes therein and configured to receive, concurrently at a plural number of the holes, an incident optical source signal that is substantially continuous in cross-section; a silicon charge P-layer under the germanium I-layer; a silicon avalanche I-layer under the silicon charge P-layer; a silicon N-layer under the silicon avalanche I-layer; and a substrate under the silicon N-region; said avalanche photodetector being configured to operate at quantum efficiency greater than 80% when receiving said incident optical source signal at a wavelength range that includes 1550 nanometers at bandwidth of at least 5 Gigabits per second, and to provide an electrical photodetector output as a function of the incident source signal when reverse-biased.