Electrodeposition of Gallium-Arsenic Alloys in Alkaline Solution

Electrodeposition of Ga-As alloys has been studied in alkaline solutions containig Ga2 (SO4)3 and As2O3. Pure arsenic was deposited at noble potentials, while the deposition of gallium was predominant at less noble potentials. Current-potential curves exhibited an arrest of current at potentials between -1.50∼-1.68V (SCE), where the deposition of GaAs took place. The deposition potential of GaAs was found to be more noble than that of pure gallium by 0.15V. The gallium content of the alloy increased with a negative shift in potential. The optimum current density for obtaining stoichiometric GaAs increased with decreases in the concentration ratio [Ga2 (SO4)3]/[As2O3] in the bath. X-ray diffraction analysis showed the deposits on titanium substrates had a clear GaAs diffraction line, while GaAs alloy deposited on copper substrates also had CuGa2 diffraction lines.