PASSIVATION OF GASB BY SULFUR TREATMENT

Some features of the band structure of GaSb have led to a renewed inte rest in this material. It is well known that Ga(Al)Sb alloys are good candidates to realize avalanche photodetectors, due to their high hole kp/electron kn ionization coefficient ratio.(1-3) In addition, recent studies have shown GaSb to be attractive for realizing tunneling barr iers exhibiting a high value of the peak-to-valley current ratio(4-6) or IR photodectectors. In order to optimize such devices, the passivat ion of GaSb is of great interest. Unfortunately, very few investigatio ns have been reported in the literature on GaSb passivation.(7-8) This paper reports experimental results concerning GaSb surface passivatio n using a chemical sulfuration method. Physicochemical analysis is att empted through ellipsometric, photoluminescence, and Auger electron sp ectroscopy measurements. Polluting oxygen and carbon agents are found to be removed from the surface using this process, leading to Schottky diodes of better quality. In addition, the sulfur treatment is shown to stabilize the cleaned surface.