High frequency space charge layer capacitance of strongly inverted semiconductor surfaces

Abstract

The finite spatial extension of the inversion layer minority carriers shunts the dielectric capacitance of the inversion layer and increases the high frequency semiconductor surface space charge layer capacitance in the strong inversion range by about 5 per cent. This distributed minority carrier distribution also gives rise to a small (about 1 per cent) high frequency capacitance minimum near the onset of strong surface inversion. A simple two-lump model is developed which is accurate to within 0·4 per cent of the numerical solution obtained from the exact transmission line model. Applied gate voltages at the capacitance minimum are presented graphically as a function of oxide thickness with the substrate impurity concentration as a parameter. Surface quantization effect is not taken into account.