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Sagfet with buffer layers

  • US 4,918,493 A
  • Filed: 08/10/1988
  • Issued: 04/17/1990
  • Est. Priority Date: 08/10/1988
  • Status: Expired due to Term
First Claim
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1. A composite buffer structure for GaAs semiconductor products on a GaAs substrate comprising:

  • a semi-insulating GaAs substrate having a first major surface on a plane oriented up to about 20 degrees towards the (1,1,1)A plane from the (1,0,0) crystalline plane;

    a first layer of epitaxial GaAs directly on said first major surface;

    an AlAs/GaAs superlattice directly on said first layer;

    a second layer of epitaxial GaAs directly on said superlattice;

    a first AlGaAs layer having a first mole fraction of Al directly on said second layer;

    a second AlGaAs layer having a second mole fraction of Al directly on said first AlGaAs layer, said second mole fraction being higher than said first mole fraction;

    a third layer of epitaxial GaAs directly on said second AlGaAs layer.

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