Patent ID: 7998808
Filing Date: 2011-08-16
Classification: H01L

Abstract:
1. A method for fabricating a semiconductor device comprising: forming a first trench mask over one surface of a semiconductor body, said first trench mask including an opening therein; removing semiconductor material from said semiconductor body from a bottom of said opening in said mask to obtain a first trench having a first width and extending to a first depth inside said semiconductor body, said first trench including sidewalls. and a bottom; forming spacers inside said first trench, each spacer extending from said bottom of said first trench along a respective sidewall thereof, said spacers being spaced from one another at said bottom of said first trench; removing semiconductor from said bottom of said first trench using said spacers as a second trench mask to obtain a second trench having a second width and extending to a second depth below said first depth inside said semiconductor body, said second width being less than said first width, said second trench including sidewalls and a bottom; covering said sidewalls and said bottom of said second trench with an insulation body; forming a field electrode inside said second trench, said source field electrode extending into said first trench; and depositing an oxide layer over said source field electrode, said spacers and said first trench.