Simultaneous diffusion of zinc and indium into GaAs: A new approach for the formation of low resistance ohmic contacts to compound semiconductors

Abstract

The simultaneous diffusion of zinc and indium into GaAs was performed prior to the deposition of a refractory contact metallization. This has resulted in low resistance contacts to p-type GaAs. We demonstrate that specific contact resistivities as low as 5×10−7 and 2×10−7 Ω cm2 are obtainable for nonalloyed and annealed contacts, respectively, using this technique. These specific contact resistances are the lowest values that have been reported for ohmic contacts to p-type GaAs. Furthermore, the apparatus used here should be easily adapted to the formation of low resistance n-type contacts by substituting for the zinc source a volatile source containing a group VI impurity such as Se or Te.