Comparison of Impact Ionization Current between PMOS and NMOS

The differences of impact ionization current between PMOS and NMOS which have similar channel conductance are discussed in detail. It is not always true that PMOS is more free of the hot carrier problems than NMOS. PMOS has two orders of magnitude larger peak-gate-current than NMOS, which can be well explained by the lower barrier height and higher electric field in PMOS.