| 摘要 |
A family of semiconductor devices formed in a semiconductor substrate of a first conductivity type, said substrate not comprising an epitaxial layer, said family comprising a trench-gated MOSFET, said trench-gated MOSFET comprising: at least four trenches formed at a surface of said substrate, a conductive gate material being disposed in each of said trenches, said gate material in each trench being separated from said semiconductor substrate by a dielectric layer, a first trench being separated from a second trench by a first mesa, said second trench being separated from a third trench by a second mesa, and said third trench being separated from a fourth trench by a third mesa; said second mesa comprising: a source region of a second conductivity type opposite to said first conductivity type adjacent a surface of said substrate and extending entirely across said second mesa, said source region having a first doping concentration of said second conductivity type; a body region of said first conductivity type adjacent said source region and extending entirely across said second mesa; and a high voltage drift region adjacent said body region and extending entirely across said second mesa, said high voltage drift region having a second doping concentration of said second conductivity type; each of said first and third mesas comprising: a drain region of said second conductivity adjacent a surface of said substrate and extending entirely across said first and third mesas, respectively, said drain region having a third doping concentration of said second conductivity type; and a well of said second conductivity type adjacent said drain region and extending entirely across said first and third mesas, respectively, said well having a fourth doping concentration of said second conductivity type; and a first layer of said second conductivity type, said first layer abutting a bottom of each of said first and second trenches and said high voltage drift region; a second layer of said second conductivity type, said second layer abutting a bottom of each of said third and fourth trenches and said high voltage drift region, said first layer being spaced apart from said second layer; wherein said first doping concentration is greater than said second doping concentration and said third doping concentration is greater than said fourth doping concentration. |
