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 3.0×10−6 Ω cm2 are obtained upon annealing in the temperature range of 800–850 °C. Contacts processed under optimum conditions show little degradation in electrical properties after 100 h of thermal aging at 400 or 500 °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.