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Depleted base transistor with high forward voltage blocking capability

  • US 5,679,966 A
  • Filed: 10/05/1995
  • Issued: 10/21/1997
  • Est. Priority Date: 10/05/1995
  • Status: Expired due to Term
First Claim
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1. A depleted base transistor comprising:

  • a semiconductor substrate having first and second opposing faces;

    a cathode contact on the first face;

    an anode contact on the second face;

    a cathode region of first conductivity type in said substrate at the first face, said cathode region forming an ohmic contact with said cathode contact;

    a trench in said substrate at the first face, said trench having a trench bottom and a trench sidewall extending between the trench bottom and the first face;

    a base region of first conductivity type in said substrate, between said cathode region and said anode contact, said base region comprising;

    a drift region of first conductivity type having a drift region doping concentration;

    a blocking voltage enhancement region of first conductivity type extending between said drift region and said cathode region, said blocking voltage enhancement region forming non-rectifying junctions with said cathode region and said drift region and having a blocking voltage enhancement region doping concentration below the drift region doping concentration;

    an insulated gate electrode in said trench; and

    means, comprising a rectifying junction in said substrate, for depleting said blocking voltage enhancement region of majority free carriers to thereby inhibit traversal of majority carriers from said cathode region to said drift region.

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