Thermal stability of AuPt/n−-GaAs Schottky contacts

The possibility of optimization and the thermal stability of AuPt Schottky contacts on n−-GaAs epitaxial layer has been investigated. The thermal treatment has been carried out in an RTA apparatus for 100 s. The contacts have been found to remain thermally stable up to 350 °C, the optimal annealing temperature is in the range 330–340 °C. The structure, which was annealed at 438 °C, has ohmic character with a contact resistivity of 3.70×10-5Ωcm2, and a thickness of the modified subcontact layer of 160 nm. The reaction between the metallization and GaAs is negligible in the case of the optimal annealing. Au and Pt react very strongly with GaAs during annealing, when the metallization is converted into an ohmic contact structure. Arsenic, as a volatile element, leaks from the structure.