Carrier mobility degradation in metal-oxide-semiconductor field-effect transistors due to oxide charge

Abstract

Radiation causes oxide charge buildup which can degrade carrier mobility in the inversion layer of a metal-oxide-semiconductor field-effect transistor (MOSFET). An expression for the carrier mobility in MOSFETs due to oxide charge scattering has been derived. The model predicts the mobility degradation given any specified charge density profile in the oxide. It accounts for screening of oxide charges by channel carriers. To validate the proposed model we performed an experiment to place a measured quantity of charge at a definite position in the gate oxide and then measured the mobility degradation. The experimental results are in good agreement with the predictions of the model.