Solid Phase Reactions of Ni-GaAs Alloys for High Mobility III–V MOSFET Applications

The solid phase reactions of Ni with GaAs substrates are investigated. The experimental results reveal that the Ni-GaAs solid phase reaction forms a ternary phase of Ni₂GaAs when annealing temperatures are in the range 250–300°C. As the annealing temperature increases to 400°C, the Ni₂GaAs phase starts to decompose due to NiAs phase precipitation. Ni−GaAs alloys processed at 400°C with a 3 min annealing time demonstrate a sheet resistance of 30 Ω/square after unreacted Ni removal in hot diluted−HCl solutions. Therefore, Ni-GaAs alloys formed by solid phase reaction could be promising metallic source/drain structures with significant low series resistance for high mobility III–V metal-oxide-semiconductor field effect transistor (MOSFET) applications.