CrPt Ohmic contacts to B ₁₂ As ₂

Palladium, Pt, and CrPt contacts to the wide band gap icosahedral boride semiconductor B12 As2 have been studied. All Pd and Pt contacts exhibited nonlinear I-V characteristics, while CrPt contacts were Ohmic. The specific contact resistance was reduced from 6 Ω cm2 as-deposited to 3× 10-4 Ω cm2 after the CrPt contacts were annealed at 750 °C for 30 s in Ar. Annealing at 600 °C or higher drastically reduced the semiconductor sheet resistance, whether annealing was performed before or after metallization. This apparent activation of the semiconductor is a likely cause for the improvement in the Ohmic contacts with annealing.