SBIR Phase I: A Complementary Metal-Oxide Semiconductor (CMOS) Compatible Single Photon Avalanche Diode

The broader impact/commercial potential of this Small Business Innovation Research (SBIR) Phase I project is to make 3D cameras for long-range LiDAR (Light Detection and Ranging) more affordable, widespread, and as reliable and simple to use as cameras found in common mobile devices. 3D cameras (LiDAR) are being used for precise positioning and velocity determination of objects in augmented reality applications and are crucial for widespread adoption of autonomous cars and trucks where the 200-300 meter range is required. Eye safety concerns with low-cost silicon sensors force the long-range autonomous vehicle customers to use one pixel at the time or limited field of view imaging using high-cost and complex systems based on materials that require specialty materials and manufacturing. This technology will enable the use of mainstream materials and process technology for the long-range autonomous vehicle segment without compromising eye safety. This capability will reduce cost, lower complexity, and improve reliability of long-range 3D cameras and help propel the autonomous vehicle industry into widespread adoption.This Small Business Innovation Research (SBIR) Phase I project aims to develop a fully complementary metal-oxide semiconductor compatible single photon avalanche diode (SPADs) based on germanium that operates at eye safe wavelengths. Current germanium-based avalanche photodiodes require cryogenic cooling due to excessive dark noise from tunneling or dislocations.They suffer from poor absorption at the eye safe wavelengths beyond 1450 nm. This project will implement a photon trapping strained heterostructure device architecture which reduces dark counts while enhancing absorption at the operating wavelength. The device structure will be developed with particular emphasis on the semiconductor growth process. The experimental results will be benchmarked to the dark count and absorption requirements for the mass-market, long-range autonomous vehicle application. The technology will offer a highly manufacturable, lower cost alternative to compound semiconductor based SPADs that are often prohibitively expensive to produce in large arrays.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.