Recent advances in very large area avalanche photodiodes

Abstract

Abstract The Avalanche Photodiode (APD) is a unique device that combines the advantages of solid state photodetectorswith those of high gain devices such as photomultiplier tubes (PMTs). APDs have internal gain that provides a highsignal-to-noise ratio. APDs have high quantum efficiency, are fast, compact, and rugged. These properties make themsuitable detectors for important applications such as LADAR, detection and identification toxic chemicals and bio-warfare agents, LIDAR fluorescence detection, stand-off laser induced breakdown spectroscopy (LIBS), and nucleardetectors and imagers.Recently there have been significant technical breakthroughs in fabricating very large APDs, APD arrays, andposition sensitive APD arrays (PSAPD). Signal gain of over 10,000 has been ach ieved, single element APDs h ave beenfabricated with active area greater than 40 cm 2 , monolithic pixelated arrays with up to 28 x 28 elements have beenfabricated, and position sensitive APDs h ave been devel oped and tested.Additionally, significant progress has been made in improving the fabrication process to provide better uniformityand high yield, pe rmitting cost effective manufacturing of APDs for reduced cost.Keywords: Avalanche Photodiode, APD, APD array, LIDAR, laser radar, chem/bio1.