Consequences of negative differential electron mobility in insulated gate field effect transistors

TL;DR

This paper investigates how negative differential electron mobility affects the behavior of short-channel insulated gate FETs, revealing unique current-voltage characteristics and potential instabilities.

Contribution

It demonstrates that negative differential mobility leads to non-monotonic current-voltage relations and possible instabilities, contrasting with traditional models.

Findings

Short-channel FETs can be described by the gradual channel approximation at high voltages.

The current-voltage characteristic exhibits a negative slope branch.

The device may show negative differential resistance and instability.

Abstract

We study the consequences of negative differential electron mobility in insulated gate field effect transistors (FETS) using the field model. We show that, in contrast to the case of the monotonic velocity saturation model, the field distributions in a short-channel FET may be described by the gradual channel approximation even for high drain-to-source voltages. The current-voltage dependence of the short-channel FET should have a branch with a negative slope. The FET exhibits a negative differential resistance and may show convective or absolute instability, depending on the applied voltages. The fluctuation growth is governed by the diffusion law with a negative effective diffusion coefficient.