Trapping Effects in Au-n-Type GaAs Schottky Barrier Diodes

Transient phenomena in capacitance ( C ) and reverse current ( I ) were observed for Au- n -Type GaAs Schottky barrier diodes at different carrier concentrations in GaAs crystals. Both ( C i -2 - C s -2 ) and I s / I i , where subscripts i and s refer to the initial condition and the steady state after voltage application, respectively, approach certain values independent of voltage at high reverse voltages but dependent of carrier concentrations and trap densities. The transient phenomena disappear in crystals of high carrier concentrations, say, 2×10 17 cm -3 . The results are explained by trapping effects in the space charge layer. The trap density in boat-grown GaAs crystals is estimated to be of the order of magnitude of 10 14 cm -3 ∼10 16 cm -3 .