NOVEL LOW-RESISTANCE OHMIC CONTACT TO N-TYPE GAAS USING CU3GE

We show that e1‐Cu3Ge forms a low‐resistance ohmic contact to n‐type GaAs. The e1‐Cu3Ge contact exhibits a planar and abrupt interface and contact resistivity of 6.5×10−7 Ω cm2 which is considerably lower than that reported for Ge/Pd and AuGeNi contacts on n‐type GaAs with similar doping concentrations (∼1×1017 cm−3). The contact is electrically stable during annealing at temperatures up to 450 °C. We also show that in the Ge/Cu/n‐type GaAs system, the contact remains ohmic over a wide range of Ge concentration that extends from 15 to 40 at. %. n‐channel GaAs metal–semiconductor field‐effect transistors using the e1‐Cu3Ge ohmic contacts demonstrate a higher transconductance compared to devices with Ge/Pd and AuGeNi contacts.