Low Cost Avalanche Photodiodes and Photodiode Arrays

Silicon avalanche photodiodes are among the most sensitive optical detectors available today. It 11as been shown that large area APDs are potentially an excellent alternative to photomultiplier tubes (PMTs) in applications such as LIDAR, nuclear medicine, physics research and nuclear radiation measurement instrumentation. They can offer improved performance based on their compact size, solid state reliability, immunity to magnetic fields, better energy resolution for nuclear applications and the potential for spatial resolution for imaging. However, due to the high cost of APD production by existing techniques, they are not now widely used. We propose to conduct the research and development necessary to implement a revolutionary APD design that can be manufactured entirely using standard automatic planar techniques employed in the IC industry. This will result in a low cost, high efficiency, high resolution alternative to PMTs which can both improve performance and reduce cost of higll performance optical and nuclear instrumentation. This approach will also lead to the ability to fabricate planar arrays of APDs for imaging applications. The development of an inexpensive replacement for PMTs would have many applications. PMTs are used in numerous scientific instruments which dedect low levels of light, such as LIDAR, spectropllotometers, and various biochemical instruments. PMTs are used in nuclear radiation detectors for nuclear medicine and in nuclear and particle physics systems. High performance APDs are already a commercial product, even at the present price. An inexpensive replacement for a PMT would find widespread commercial appeal.