Integrated bulk/SOI APD sensor: bulk substrate inspection with Geiger-mode avalanche photodiodes

A rapid assessment of bulk silicon quality after removal of the silicon-on-insulator (SOI) and buried oxide layer using both plasma and wet etch is compared with standard p-epi silicon by comparing the performance of avalanche photodiodes (APD) operated in Geiger-mode. Plasma etching of the buried oxide shows lower dark counts than wet etched or standard p-epi substrates.