PtIn2 ohmic contacts to n-GaAs via an In-Ga exchange mechanism

Using sputter-deposited PtIn2 films as metallizations, it is demonstrated that the recently identified exchange mechanism may be utilized to form ohmic contacts to n-GaAs. Specific contact resistances as low as 3.0x10-6 Ωcm2 are obtained upon annealing in the temperature range of 800 endash 850 degree C. Contacts processed under optimum conditions show little degradation in electrical properties after 100 h of thermal aging at 400 or 500 degree C. Auger depth profiles of as-deposited and annealed samples are consistent with the hypothesis of an exchange of In and Ga atoms at the contact interface. copyright 1996 American Institute of Physics