Critical analysis of the substrate hot-hole injection technique

Abstract To explore its potentials and limitations as a technique for the controlled injection of holes in the study of degradation phenomena in MOSFETs, the substrate hot-hole injection technique has been analyzed in detail. The minority carrier flow and the corresponding potential drop in the channel during operation has been analytically modeled. The nature of the measured gate current has been examined. The gate current is, at moderate oxide fields and trapped charge levels, uniquely consisting of holes injected uniformly from the silicon substrate into the gate oxide, while under very high oxide field and/or trapping conditions, simultaneous injection of electrons from the gate may occur. The hot-hole injection probability at 295 K has been modeled with a “lucky-hole” model, that takes into account over-the-barrier injection as well as through-the-barrier tunneling. Due to backtunneling of injected holes, the effective injection probability at 77 K is smaller than at 295 K. It is concluded that under proper operating conditions, substrate hot-hole injection is a powerful and reliable technique.