Modeling the capacitance-voltage response of In_0.53Ga _0.47 As metal-oxide-semiconductor structures: Charge quantization and nonparabolic corrections

The capacitance-voltage (C-V) characteristic is calculated for p-type In0.53 Ga0.47 As metal-oxide-semiconductor (MOS) structures based on a self-consistent Poisson-Schrödinger solution. For strong inversion, charge quantization leads to occupation of the satellite valleys which appears as a sharp increase in the capacitance toward the oxide capacitance. The results indicate that the charge quantization, even in the absence of interface defects (Dit), is a contributing factor to the experimental observation of an almost symmetric C-V response for In0.53 Ga0.47 As MOS structures. In addition, nonparabolic corrections are shown to enhance the depopulation of the valley, shifting the capacitance increase to lower inversion charge densities.