High-Performance Geiger Mode 1.06 micron APD Array

Conventional InGaAs/InP based APDs have very poor multiplication noise performance. While InGaAs is an excellent infrared absorber, it is a poor signal multiplier. InGaAs/InP APD devices also exhibit poor dark current and afterpulsing characteristics,which result in false signals and makes their utility for Geiger mode detection problematic. In contrast, silicon is an excellent multiplier, but unfortunately is a poor absorber in the infrared.To overcome these limitations, we will optimize a NIR Geiger mode APD focal plane array that combines the excellent NIR absorption characteristics of InGaAs and the nearly ideal multiplication characteristics of silicon by fusing InGaAs and Si in a waferbonded InGaAs-Si APD. The proposed APD structure has very low dark current and uniquely does not exhibit afterpulse-induced false signals. This is due to the fact that any holes trapped at the InGaAs/Si interface during avalanche, when released, do nottravel through the high field region of the device, and therefore do not create after-pulse currents. Unlike conventional APD devices, the fused InGaAs:Si APD design allows each of the APD layers (absorption, multiplication, and charge separation) to beindependent tailoring before device integration and, therefore, the proposed device construct readily lends itself to optimization of the critical APD performance characteristics.We will design the APD to be optimized for 1.06 to 1.55 micron NIR response, in a 32 by 32 element area array with low dark count, high bandwidth, Geiger Mode operation.. There are a number of markets that will benefit from the proposed innovation. These include, fluorescence microscopy and spectroscopy, confocal microscopy, neural imaging, chem/bio hazard detection, eyesafe ladar & lidar, telecommunications, quantumcryptology, high data rate satellite communications, ground-to-space communications, and astronomy.