MOS GATE DEVICE WITH BURIED GATE AND MANUFACTURE THEREOF

摘要

PROBLEM TO BE SOLVED: To provide a MOS transistor with a trench gate structure. SOLUTION: A trench MOS gate device includes a single crystal semiconductor substrate 201 with a doped layer thereon. The upper layer has a plurality of main regions heavily doped with first polarity on an upper surface and extended over a drain region 203. The upper layer includes a plurality of source regions heavily doped with second polarity reverse to that of the main region. The gate trench 207 is extended from an upper surface 214 of the upper layer to the drain region 203 to separate the source region from the next region. The gate trench 207 has a floor 209 made of a dielectric layer, and a side wall 208. The gate trench 207 includes an insulating layer made of a conductive gate material contained with a selected level and a dielectric material extended over a gate material 210. In this case, the gate trench 207 is filled substantially with the dielectric material.