The effect of (NH/sub 4/)/sub 2/S passivation treatments on the dark current-voltage characteristics of InGaAsSb PIN detector

InGaAsSb/GaSb detector is very promising for novel applications in long-wavelength range (>2 /spl mu/m). Dark current, composed of surface and volume currents, is a leading source of the electronic noise. Due to a large density of surface states of the InGaAsSb surface, the surface recombination current is the dominant factor in the whole dark current. In this paper, the influence of alkali and neutralized (NH/sub 4/)/sub 2/S passivation on the dark current density of InGaAsSb PIN detector has been studied. A new modified neutralized (NH/sub 4/)/sub 2/S passivation method was proposed. Results show a drastic improvement of the device characteristics was obtained by the modified neutralized (NH/sub 4/)/sub 2/S passivation. In our experiment, the PIN detectors were taken from the same epitaxial wafer and prepared by same fabrication process. In order to compare the effect of different (NH/sub 4/)/sub 2/S passivation solution, the devices were divided into two groups. The results indicate that the sulfur-passivation can remove native oxide and depress surface stats of InGaAsSb effectively.