A hybrid surface passivation on HgCdTe long wave infrared detector with in-situ CdTe deposition and high-density hydrogen plasma modification

A hybrid surface passivation, in-situ CdTe passivation and high-density hydrogen plasma modification, is used to improve the surface quality of typical n+-on-p HgCdTe long wave infrared photodiode detectors. Three types of surface-passivated pixels, conventional, in-situ CdTe, and hybrid surface passivation, are fabricated in one chip for better comparison. The maximum dynamic resistances of the hybrid-surface-passivation device are increased to 1∼2 times greater than that in the conventional surface passivation technique. Theoretical modeling shows that the hybrid passivation can significantly suppress the trap-assisted tunneling current. Shallow traps close to the Fermi level under reverse voltage, which are the main source of the trap-assisted tunneling current for conventional surface passivation processing, are reduced by the hybrid passivation treatment.