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Nanosheet substrate to source/drain isolation

  • US 10,734,523 B2
  • Filed: 08/13/2018
  • Issued: 08/04/2020
  • Est. Priority Date: 08/13/2018
  • Status: Active Grant
First Claim
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1. A method of forming a nanosheet device, comprising:

  • forming a nanosheet channel layer stack and dummy gate structure on a substrate;

    forming a curved recess in the substrate surface adjacent to the nanosheet channel layer stack;

    depositing a protective layer on the curved recess, dummy gate structure, and exposed sidewall surfaces of the nanosheet layer stack;

    removing a portion of the protective layer on the curved recess to form a downward-spiked ridge around the rim of the curved recess;

    extending the curved recess deeper into the substrate to form an extended recess; and

    forming a sacrificial layer at the surface of the extended recess in the substrate.

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