Thermodynamically stable tungsten ohmic contacts to n-In0.53Ga0.47As

Abstract

Based on a thermodynamic assessment of the W–In–Ga–As quaternary system, the metal W was selected as a thermodynamically stable ohmic contact material to n-In0.53Ga0.47As. As-deposited contacts (on n ∼ 1.4 × 1018 cm−3 In0.53Ga0.47As) had average specific contact resistances of 7 × 10−7 Ω ·cm2 as measured using the transmission line model. The contact resistances remained unchanged after rapid thermal annealing at 400 °C for 1 min or at 600 °C for 1 min, and exhibited no degradation in electrical properties even after long-term annealing at 500 °C for 100 h. Transmission electron microscopic examination of the contacts showed no interfacial reaction. The present investigation demonstrates the power of thermodynamics in identifying stable ohmic contacts to multicomponent semiconductors.