TRENCH-GATE SEMICONDUCTOR DEVICES AND THEIR MANUFACTURE

摘要

Trench-gate field-effect semiconductor devices, for example cellular power MOSFETs with compact geometries, comprise a semiconductor body (10) into which the trench-gate (11) extends from a surface-adjacent source region (13) through a channel-accommodating region (15) of opposite conductivity type (p) and into an underlying drain drift region (14). This invention provides the gate trench (20) with a width (w) that is smaller than its depth (d) and that tapers increasingly towards the bottom of the gate trench (20) to reduce the width (w) of the trench-gate (11) at a greater rate in the drain drift region (14) than in the channel-accommodating region (15).