New method for the electronic and chemical passivation of GaAs surfaces using CS ₂

A new GaAs surface passivation method, CS ₂ treatment at moderate temperature was developed for effective passivation of GaAs surfaces. The CS ₂ treatment of GaAs surfaces at 350 °C and 10 atm leads to deposition of a homogeneous film, with a thickness of several hundred angstrom. The passivation layer thus produced causes a significant enhancement in room temperature photoluminescence intensity and the passivation effect of the sulfide film was confirmed by Raman spectroscopy. The passivation layer remained electrically and chemically stable over a period of nine months under ambient atmospheric conditions. In-depth Auger electron spectroscopy (AES) revealed that the carbon and oxygen content in the film was negligible, whereas sulfur was uniformly distributed throughout the film. A metal-insulator-semiconductor diode whose insulating layer is produced by the CS ₂ treatment shows well-defined accumulation and depletion regions in its capacitance-voltage (C-V) characteristics with low hysteresis.