SULFUR AND HYDROGEN PASSIVATION EFFECTS ON THERMAL-STABILITY OF RUO2 SCHOTTKY CONTACT ON N-TYPE GAAS

Effects of sulfur and hydrogen passivation on the thermal stability of RuO2 Schottky contacts on n-type GaAs have been studied by treatments with (NH4)(2)S-x solution and hydrogen plasma, respectively. The RuO2 thin films were deposited by de magnetron sputtering using a Ru targe t and a mixture of argon and oxygen gases. The thermal stability of Ru O2 Schottky contacts during thermal annealing in the temperature range from 200 to 550 degrees C for 10 min was investigated by current-volt age (I-V) measurements and Auger electron spectroscopy, For the sulfur treated sample, the ideality factor was constant at about 1.01 in the whole temperature range and the barrier height of 0.84 eV was maintai ned up to 350 degrees C. Hydrogenation treatment, however, was not so effective in preventing the thermal degradation compared to the sulfur ization process, It is confirmed that the effective sulfur passivation to enhance the thermal stability of RuO2/GaAs is responsible for the suppression of an oxidation in the interface between GaAs and RuO2. (C ) 1995 American Institute of Physics.