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Method of forming shaped source/drain epitaxial layers of a semiconductor device

  • US 10,516,037 B2
  • Filed: 11/01/2017
  • Issued: 12/24/2019
  • Est. Priority Date: 06/30/2017
  • Status: Active Grant
First Claim
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1. A method for manufacturing a semiconductor device, comprising:

  • forming an isolation insulating layer over a fin structure, wherein a first portion of the fin structure is exposed from the isolation insulating layer and a second portion of the fin structure is embedded in the isolation insulating layer;

    forming a gate structure over a part of the first portion of the fin structure;

    forming a dielectric layer over sidewalls of the first portion of the fin structure in a source/drain region not covered by the gate structure;

    removing the first portion of the fin structure and a part of the second portion of the fin structure between portions of the dielectric layer in the source/drain region, thereby forming a trench over a remaining part of the second portion of the fin structure and between the portions of the dielectric layer that extend along an entire length of the trench; and

    forming a source/drain (SD) epitaxial structure in the trench using one of a first process or a second process,wherein a top surface of the remaining part of the second portion of the fin structure in the trench provides a preferred crystallographic facet, and the first process comprises an enhanced epitaxial growth process having an enhanced growth rate for the preferred crystallographic facet,the second process comprises disposing an SD epitaxial structure in the trench and on top of the trench and using a modified etch process to reduce a width of the SD epitaxial structure on top of the trench, andafter either of the first process or the second process a lateral extent of the SD epitaxial structure on top of the trench is limited to about sidewalls of the portions of the dielectric layer that are further away from the trench.

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