Comparative studies on Al-Ge-Ni and Al-Sn-Ni ohmic contacts to n-type GaAs

Abstract

Al-Ge-Ni and Al-Sn-Ni metallization schemes for ohmic contacts to n-type GaAs are compared on their specific contact resistance, thermal stability, and surface morphology. Both metallization schemes exhibit specific contact resistance in the 10 −5 Ω cm 2 range. The thermal stability of both types of contacts is excellent with little degradation even after 1000 h of aging at 100 °C. Al-Sn-Ni ohmic contacts show vastly improved surface morphology compared to that of Al-Ge-Ni ohmic contacts. Both types of contacts, however, show much smoother surface morphology than that of AuGeNi ohmic contacts.