The effect of internal field distribution on quasi-two-dimensional modelling of short-channel MOSFETs

Abstract

Being a prime factor in modelling short-channel MOSFETs, the internal field distribution is extensively examined. The effect of uniform, linear and parabolic distributions on quasi-two-dimensional modelling of short-channel MOSFETs is presented. The drain characteristics and small signal parameters arc proved to be almost insensitive to the field distribution. The modelled hot-carrier currents agree well with the experimental data available in the literature for a linear field distribution. The gate current has proved to be much more sensitive to the field distribution than the substrate current. Il is also proved that the more nonlinear the field distribution, the longer the channel length of reliable devices. It is deduced that devices less than 0-5 μm in channel length possess the same maximum allowable drain voltage irrespective of the field distribution.