New physical model of multiplication-induced breakdown in MOSFETs

Abstract

The thesis of this paper is that the mechanism of multiplication-induced breakdown is essentially different from what has previously been thought. Two consecutive phases of the breakdown: enhanced body effect (EBE) and parasitic bipolar action have to be distinguished. It is shown that the difference between the EBE and the ordinary body effect results from the fact that the body effect does not involve any electrical field, whereas EBE has to account for a nonzero field in the bulk, necessary to drive the substrate current. Similarly the bipolar action may be treated in terms of a parasitic bipolar transistor, but only on condition that the variable geometry and unconventional mode of biasing of the base are taken into account. It has been found that the size of the base increases considerably with V DS. In addition, the base bias V be is not equal to V sub − V sub = R sub I sub becomes entirely constant) but rather to V sub + δΨ − V SB, where δΨ has been explicitly related to the substrate current I sub. The new physical model of multiplication-induced breakdown has been verified and confirmed according to numerical simulation results. Furthermore, the analytical predictions based on it agree very closely with measured drain and substrate current characteristics.