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Angle implant process for cellular deep trench sidewall doping

  • US 6,509,240 B2
  • Filed: 05/10/2001
  • Issued: 01/21/2003
  • Est. Priority Date: 05/15/2000
  • Status: Expired due to Term
First Claim
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1. A process of manufacture of a superjunction device comprising the steps of forming spaced parallel trenches into a silicon wafer of one conductivity type;

  • each of said trenches having an axis along a depth dimension with said axes being perpendicular to a top surface of said silicon wafer;

    each of said trenches having approximately a same depth and cross section;

    directing an implant beam of a species which defines a second conductivity type toward said top surface of said silicon wafer and at an angle to said axes of each of said trenches;

    said angle being sufficiently small that a full length of an interior surface of each of said trenches receives implanted ions from said implant beam;

    rotating said wafer to expose a full surface area of an interior of each of said trenches to said implant beam; and

    maintaining said implant beam directing and said wafer rotating until a sufficient depth and concentration of said second conductivity type is achieved to match that of said silicon wafer when activated, such that regions near said trenches of opposite conductivity type both deplete during reverse bias.

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