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Method of manufacturing an LDDFET having an inverted-T shaped gate electrode

  • US 5,147,814 A
  • Filed: 07/22/1991
  • Issued: 09/15/1992
  • Est. Priority Date: 03/28/1989
  • Status: Expired due to Term
First Claim
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1. A method of manufacturing a semiconductor device, comprising the steps of:

  • providing a substrate composed of a semiconductor material of a first conductivity type, the substrate having an outer surface;

    forming a first insulating film on the outer surface of the substrate;

    forming a first conductive film on the first insulating film and forming a second conductive film on the first conductive film, each conductive film having two opposed edges;

    forming the first and second conductive film into an MOS transistor gate electrode having a defined shape including two opposed sides, respective portions of which sides are defined by the two opposed edges of the conductive films;

    effecting thermal annealing of the gate electrode for causing the opposed edges of the second conductive film to be spaced inwardly of the opposed edges of the first conductive film; and

    performing ion implantation of impurity ions of a second conductivity type, opposite to the first conductivity type, into the substrate, via the outer surface, with the gate electrode acting as a mask with respect to the impurity ions, said step of performing ion implantation being carried out with a type of impurity and with an ion accelerating voltage selected such that the impurity ions cannot traverse a path through both the first conductive film and the second conductive film but can traverse a path through only the first conductive film.

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