PD-GE CONTACT TO N-GAAS WITH THE TIW DIFFUSION BARRIER

Abstract

Pd-Ge based ohmic contact to n-GaAs with a TiW diffusion barrier was investigated. Electrical analysis as well as Auger electron spectroscopy and the scanning electron microscopy were used to study the contact after it was subjected to different furnace and rapid thermal annealing and different aging steps. All analyses show that TiW can act as a good barrier metal for the Au/Ge/Pd/n=GaAs contact system. A value of 1.45 x 10(-6) OMEGA-cm2 for the specific contact resistance was obtained for the Au/TiW/Ge/Pd/n-GaAs contact after it was rapid thermally annealed at 425-degrees-C for 90 s. It can withstand a thermal aging at 350-degrees-C for 40 h with its pc increasing to 2.94 x 10(-6) OMEGA-CM2 and for an aging at 410-degrees-C for 40 h with its p. increasing to 1.38 x 10(-5) OMEGA-cm2.