ANOMALOUS GATE LENGTH DEPENDENCE OF THRESHOLD VOLTAGE OF TRENCH-ISOLATED METAL-OXIDE-SEMICONDUCTOR FIELD-EFFECT TRANSISTORS

We investigate the influence of trench isolation edges on metal oxide semiconductor field effect transistors (MOSFETs) by comparison with th e characteristics of a reference transistor with no isolation edge. Th e result indicates that the gate length (Lf dependence of the threshol d voltage (V-th) is remarkably modified by an electric field concentra tion at the channel edge. The anomalous V-th, behavior is explained in terms of the mixing between the short and narrow channel effects, by a qualitative three-dimensional analysis.