Abstract
A closed-form analytical expression is derived to predict the threshold voltage of a narrow-gate metal-oxide-semiconductor field-effect transistor with a fully recessed field-isolation structure. The calculation is based on a simple conformal transform and a physical model employing the depletion approximation. The physical origin of the inverse narrow-gate effect is mentioned. Threshold-voltage variations under the influence of various physical parameters are discussed, and a comparison with published data shows that the present model is useful.