Thermally stable tungsten ohmic contact to p-InGaAs and effective barrier height measurement by using the I-V-T method

Tungsten (W) contacts to p-In0.53Ga0.47As (Be: 2.5 x 10(19) cm(-3)) were fo rmed by using the rapid thermal annealing (RTA) process. The W/p-In0.53Ga0. 47As contacts were rectifying in the as-deposited state as well as after he at treatment at temperatures higher than 750 degreesC for 30 sec. The therm al annealing of the contacts in the temperature range of 400 similar to 700 degreesC for 30 sec and at 750 degreesC for under 20 sec produced ohmic be havior. The lowest specific contact resistance of 3.76 x 10(-6) Omega cm(2) was obtained for the sample annealed at 400 degreesC for 30 sec. The therm al stability and the specific contact resistance were investigated at vario us annealing temperatures to obtain the optimum conditions. In order to def ine the carrier transport mechanism, we measured the I-V (current-voltage) and specific resistance characteristics after each RTA process at different temperatures between 25 degreesC and 190 degreesC. The effective barrier h eight was estimated using the curve fittings from theoretical calculation a nd experimental data.