PTIN2 OHMIC CONTACTS TO N-GAAS VIA AN IN-GA EXCHANGE MECHANISM

Using sputter-deposited PtIn2 films as metallizations, it is demonstra ted that the recently identified exchange mechanism may be utilized to form ohmic contacts to n-GaAs. Specific contact resistances as low as 3.0 X 10(-6) Omega cm(2) are obtained upon annealing in the temperatu re range of 800-850 degrees C. Contacts processed under optimum condit ions show little degradation in electrical properties after 100 h of t hermal aging at 400 or 500 degrees C. Auger depth profiles of as-depos ited and annealed samples are consistent with the hypothesis of an exc hange of In and Ga atoms at the contact interface. (C) 1996 American I nstitute of Physics.