PROCESS FOR MANUFACTURE OF HIGH POWER MOSFET WITH LATERALLY DISTRIBUTED HIGH CARRIER DENSITY BENEATH THE GATE OXIDE

摘要

PROCESS FOR MANUFACTURE OF HIGH POWERMOSFET WITH LATERALLY DISTRIBUTED HIGH CARRIERDENSITY BENEATH THE GATE OXIDEABSTRACT OF THE DISCLOSUREA high power MOSFET structure consists of aplurality of source cells distributed over the uppersurface of a semiconductor chip, with a drain electrodeon the bottom of the chip. Each of the source cells ishexagonal in configuration and is surrounded by anarrow, hexagonal conduction region disposed beneath agate oxide. The semiconductor material beneath thegate oxide has a relatively high conductivity, with thecarriers being laterally equally distributed in densitybeneath the gate oxide. The high conductivity hexagonalchannel is formed in a low conductivity epitaxiallyformed region and consists of carriers deposited on theepitaxial region prior to the formation of the sourceregion. Symmetrically arranged gate fingers extendover the upper surface of the device and extend throughand along slits in the upper source metallizing and areconnected to a polysilicon gate grid which overlies thegate oxide.