Effect of passivation on selectively grown sub-µm Ge-on-Si single photon avalanche diode detectors

Ge-on-SOI (silicon-on-insulator) single photon avalanche diodes (SPADs) have been fabricated with exposed sidewalls allowing variation of passivation techniques. Reduced dark currents and density of surface states are demonstrated with thermal oxide passivation, demonstrating the benefit of optimal passivation of low aspect ratio selectively grown Ge.