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Ultra-short channel recessed gate MOSFET with a buried contact

  • US 5,877,056 A
  • Filed: 01/08/1998
  • Issued: 03/02/1999
  • Est. Priority Date: 01/08/1998
  • Status: Expired due to Term
First Claim
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1. A method of forming a transistor in a semiconductor substrate, said semiconductor substrate having an isolation region, said method comprising the steps of:

  • forming a pad insulator layer over said semiconductor substrate;

    forming a stacked layer stacked over said pad insulator layer;

    removing a portion of said stacked layer for having an gate insulator space in said stacked layer to said pad insulator layer;

    forming a gate insulator within said gate insulator space over said semiconductor substrate;

    doping a lightly doped region with a first concentration of a first dopant type in said semiconductor substrate uncovered by said gate insulator and said isolation region;

    removing said stacked layer and said pad insulator layer;

    forming a semiconductor layer over said semiconductor substrate;

    removing a portion of said semiconductor layer over said gate insulator to define a space over said gate insulator;

    forming spacer structure in said space on a sidewall portion of said semiconductor layer;

    removing a portion of said gate insulator for having a gate space over said semiconductor substrate;

    doping an anti punchthrough region in said semiconductor substrate under said gate space with a second concentration of a second dopant type;

    forming a first insulator layer on said semiconductor substrate under said gate space and on said semiconductor layer;

    forming a gate filling to fill within said gate space;

    removing a portion of said first insulator layer which is uncovered by said gate filling;

    doping a plurality of junction ions with a third concentration of a third dopant type into said semiconductor layer;

    forming a second insulator layer over said semiconductor substrate;

    performing a thermal process to said semiconductor substrate; and

    performing a metalization process on said semiconductor substrate.

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