Cubic zirconia as a species permeable coating for zinc diffusion in gallium arsenide

Diffusion of zinc into GaAs through an yttria-stabilized cubic zirconia (YSZ) passivation layer has been demonstrated with an open-tube diffusion method. Pure zinc or GaAs/Zn2As3 sources produced high quality planar p-n junctions. The YSZ layer protects the GaAs surface from excessive loss of arsenic, yet is permeable to zinc, allowing its diffusion into the semiconductor. The YSZ films, deposited by electron beam evaporation, were typically 2000 Å thick. Zinc diffusion coefficients (DT) at 650 °C in the YSZ passivated GaAs ranged from 3.6×10−10 cm2/min for the GaAs/Zn2As3 source to 1.9×10−9 cm2/min for the pure zinc source. Doping concentrations for both YSZ passivated and uncapped samples were approximately 5×1019 cm−3.