THERMODYNAMICALLY STABLE TUNGSTEN OHMIC CONTACTS TO N-IN0.53GA0.47AS

Based on a thermodynamic assessment of the W-In-Ga-As quaternary syste m, the metal W was selected as a thermodynamically stable ohmic contac t material to n-In0.53Ga0.47As. As-deposited contacts (on n similar to 1.4 x 10(18) cm(-3) In0.53Ga0.47As) had average specific contact resi stances of 7 x 10(-7) Omega.cm(2) as measured using the transmission l ine model. The contact resistances remained unchanged after rapid ther mal annealing at 400 degrees C for 1 min or at 600 degrees C for 1 min , and exhibited no degradation in electrical properties even after lon g-term annealing at 500 degrees C for 100 h. Transmission electron mic roscopic examination of the contacts showed no interfacial reaction. T he present investigation demonstrates the power of thermodynamics in i dentifying stable ohmic contacts to multicomponent semiconductors.