Semiconductor device having silicon-germanium source/drain regions with varying germanium concentrations

  • US 9,761,719 B2
  • Filed: 06/17/2015
  • Issued: 09/12/2017
  • Est. Priority Date: 07/22/2014
  • Status: Active Grant
First Claim
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1. A semiconductor device comprising:

  • a semiconductor substrate;

    a device isolating layer embedded within the semiconductor substrate and defining an active region;

    a channel region formed in the active region;

    a gate electrode disposed above the channel region;

    a gate insulating layer provided between the channel region and the gate electrode;

    a silicon germanium epitaxial layer adjacent to the channel region within the active region and including a first epitaxial layer containing a first concentration of germanium, a second epitaxial layer containing a second concentration of germanium, higher than the first concentration, and a third epitaxial layer containing a third concentration of germanium, lower than the second concentration, the first to third epitaxial layers being sequentially stacked on one another in that order; and

    a silicon capping layer and an etch stopping layer,wherein the silicon capping layer and etch stopping layer are sequentially disposed on the silicon germanium epitaxial layer.

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