Quantization effects in inversion layers of PMOSFET's on Si(100) substrates

The 2-D hole gas distributions within inversion layers of PMOSFET's have been evaluated by solving the coupled Schrodinger equation and Poisson equation self-consistently based on the effective-mass approximation with the light hole and heavy hole subbands taken into account The threshold voltage shift resulting from the carrier redistribution due to quantization effects is found to be more significant for PMOSFET's than NMOSFET's on (100) Si substrates, For a certain substrate doping concentration, the threshold voltage shift from the classical value due to quantization effects is found to be a combination of substrate band bending and oxide potential differences between the classical and the quantum mechanical models.