S2CL2 TREATMENT - A NEW SULFUR PASSIVATION METHOD OF GAAS SURFACE

We have developed a new sulfur passivation method-S2Cl2 treatment, which is quite effective for removing the surface oxide layer of GaAs and passivating the surface with monolayer thick sulfides. Photoluminescence (PL) spectroscopy, Auger electron spectroscopy (AES), and x-ray photoelectron spectroscopy (XPS) are used to study the passivated GaAs (100) surfaces. The results of PL reveal that the PL intensity increases by two orders of magnitude, which is indicative of the reduction of surface recombination velocity of GaAs by this treatment. AES data prove that the sulfurized surface contains S, Ga, As, C, and small amount of Cl atoms but no oxygen signal at all. XPS study shows that sulfur atoms bond to both Ga and As atoms more effectively on S2Cl2 treated surfaces than those passivated by (NH4)2Sx.