Dominant mechanisms of hot-carrier degradation in short- and long-channel transistors

Abstract

Using our physics-based model for hot-carrier degradation (HCD) we analyze the role of such important processes as the Si-H bond-breakage induced by a solitary hot carrier, bond dissociation triggered by the miltivibrational excitation of the bond, and electron-electron scattering. To check the roles of these mechanisms we use planar CMOS devices with gate lengths varying between 65 and 300 nm as well as a high-voltage nLDMOS transistor. We show that the current HCD paradigm needs to be revised because the aforementioned processes can be crucial even under stress conditions at which they are supposed to be weak.

On the limits of applicability of drift-diffusion based hot carrier degradation modeling

“…Note that in a real device subjected to hot-carrier stress both cold and hot carriers are present, and thus both mechanisms contribute. 14,15) As a consequence, to evaluate the rates of these two competing processes one needs to distinguish between "cold" and "hot" carriers. Therefore, the key point in HCD modeling is to know how carriers are distributed over energy.…”