Submicron and low-temperature ohmic contacts on δ-doped GaAs

Abstract

Practical nonalloyed ohmic contacts on δ-doped GaAs have been compared for AuGeNi (88:12:5) /and Cr metallizations to show the importance of metallization type for minimizing the contact resistance. They are shown to have low contact resistances even at 4.2 K and for contact sizes down to 240 nm diam. The effect of heating AuGeNi contacts to 270 °C is shown to be beneficial for large-area contacts but not for submicron contacts, implying that nonuniformity is introduced.