Temperature studies of sulfur passivated GaAs(100) contacts

Good ohmic contacts are essential for high speed devices and nuclear detector applications. Sulfur adsorption onto GaAs surfaces has been shown to be very effective in forming good ohmic contacts. Thermal desorption results of residual gas analysis and Auger electron spectroscopy show that the desorption of oxygen and sulfur from passivated GaAs(100) surfaces occurs over the temperature ranges of 400–500 °C and 520–600 °C, respectively. The oxygen signal disappears when sulfur decreases at 500 °C, and the sulfur signal disappears at 600 °C. The reliability of the contacts on doped passivated GaAs has shown the loss of ohmicity above 200 °C. The correlation of the physical and electrical characterizations of the contacts on doped materials are also discussed.