Trap depth and electron capture cross section determination by trap refilling experiments in Schottky diodes

It is shown that the time-dependent capacitance change associated trap refilling in a Schottky diode is nonexponential, consisting in the sum of two contributions which reduce to a single one for reverse biases smaller than VSCO, the space-charge crossover voltage. Determination of VSCO yields both the trap depth ΔE and its capture cross section. This is experimentally demonstrated for the oxygen-related trap in n-GaAs. We find ΔE=0.67 eV in good agreement with other determinations.