C-V analysis of the Schottky barrier in semi-insulating semiconductors

Abstract

We analyze the screening length and the base series admittance effect on the measurement of the barrier capacitance and voltage in semi-insulating (SI) semiconductors. Specific experimental conditions are summarized which enable the utilization of C-V analysis in SI materials. It is shown that under such experimental conditions the formula of Sah and Reddi for low-frequency C-V dependence can be applied for the calculation of the concentration of residual shallow impurities. These considerations are applied for the low-frequency C-V analysis of the Schottky barrier in SI GaAs:Cr formed by Au contact and the concentration of residual shallow donors is determined. Some limitations of the presented C-V analysis are discussed.