Auger recombination-enhanced hot carrier degradation in nMOSFETs with a forward substrate bias

Abstract

Enhanced hot carrier degradation in nMOSFETs with a forward substrate bias is observed. The degradation cannot be explained by conventional channel hot electron effects. Instead, an Auger recombination-assisted hot electron process is proposed. In the process, holes are injected from the forward-biased substrate and provide for Auger recombination with electrons in the channel thus substantially increasing channel hot electron energy. Measured hot electron gate-current and the light emission spectrum provide evidence that the high-energy tail of channel electrons is increased with a positive substrate bias. The drain current degradation is about ten time's more serious in forward-biased substrate mode than in standard mode. The Auger-enhanced degradation exhibits positive temperature dependence and may appear to be a severe reliability issue in high temperature operation condition.