MOSFET structure and fabrication process implemented by forming deep and narrow doping regions through doping trenches

US5895951A · kind A · utility

Assignee

• MegaMOS Corporation · US

Inventors

• Koon Chong So · Fremont, US
• Yan Man Tsui · Union City, US
• Fwu-Iuan Hshieh · Saratoga, US
• True-Lon Lin · Cupertino, US
• Danny Chi Nim · San Jose, US

Key dates

• Filing date: Apr 5, 1996
• Grant date: Apr 20, 1999
• Expiry date: Apr 5, 2016

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D62/157

Abstract

This invention discloses a MOSFET device which includes a plurality of vertical cells each includes a source, a drain, and a channel for conducting source-to-drain current therethrough. Each of the vertical cells is surrounded by a polysilicon layer acting as a gate for controlling the source-to-drain current through the channel. The MOSFET device further include a plurality of doping trenches filled with trench-filling materials, The MOSFET device further includes a plurality of deep-doped regions disposed underneath the doping trenches wherein the deep-doped region extends downwardly to a depth which is substantially a sum of an implant depth of the deep-doped region and a vertical diffusion depth below a bottom of the doping trenches.