×

Metal insulator semiconductor transistor having guard region and semiconductor device having the same

  • US 5,170,241 A
  • Filed: 12/06/1990
  • Issued: 12/08/1992
  • Est. Priority Date: 12/08/1989
  • Status: Expired due to Fees
First Claim
Patent Images

1. A field effect transistor comprising:

  • a semiconductor substrate having a first conduction type and functioning as a drain region of said field effect transistor;

    a back gate region formed in said semiconductor substrate and having a second conduction type opposite to said first conduction type;

    a source region formed in said back gate region and having the first conduction type;

    an insulator film formed on said semiconductor substrate and having first an second windows, said first window being located at a portion of the insulator film where said back gate region and said source region are adjacent to each other at a surface portion of said semiconductor substrate and are exposed via said first window;

    a gate electrode covered by said insulator film and located above a surface portion of said back gate region between said source region and said drain region, said surface portion of said back gate region functioning as a channel;

    a guard region formed in said semiconductor substrate and located close to said back gate region, said guard region having the second conduction type and having a first portion located on a first side of said guard region facing said back gate region and a second portion located on a second side opposite to said first side, said the first portion being formed deeper in said semiconductor substrate than said second portion, a first breakdown voltage obtained at a first junction between said second portion and said semiconductor substrate being lower than that obtained at a second junction between said back gate region and said semiconductor substrate, said second window being located on an outer surface portion of said first portion closer to said second portion that said back gate region, and said second window exposing a part of said first portion; and

    an electrode formed on said insulator film and connecting said back gate region and said guard region via said first and second windows.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×