Method for Semiconductor Device Fabrication with Improved Epitaxial Source/Drain Proximity Control

A method, comprising:

• receiving a structure having a semiconductor substrate with a first region and a second region, a first fin over the first region, a first gate structure engaging the first fin, a second fin over the second region, a second gate structure engaging the second fin, and gate spacers over sidewalls of the first and second gate structures;
• forming a first masking element covering the second region;
• performing a first etching process to the first fin while the first masking element is over the second region, thereby resulting in a first recess proximate the first gate structure, wherein the first recess extends under the gate spacers for a first distance;
• removing the first masking element;
• forming a second masking element covering the first region;
• performing a second etching process to the second fin while the second masking element is over the first region, resulting in a second recess proximate the second gate structure, wherein the second recess extends under the gate spacers for a second distance that is smaller than the first distance, wherein a difference between the first and second distances is due to at least one parameter in the first and second etching processes being different;
• epitaxially growing a first semiconductor material in the first recess;
• and
• epitaxially growing the first semiconductor material in the second recess, wherein a volume of a first portion of the first semiconductor material above the first fin is larger than a volume of a second portion of the first semiconductor material above the second fin.

A semiconductor device, comprising:

• a substrate with a first region and a second region;
• first and second fins over the first and second regions, respectively;
• first and second gate structures engaging the first and second fins, respectively;
• gate spacers over sidewalls of the first and second gate structures;
• a first epitaxial feature at least partially embedded in the first fin and proximate the first gate structure;
• and
• a second epitaxial feature at least partially embedded in the second fin and proximate the second gate structure, wherein a first distance between the first epitaxial feature and the first gate structure along the first fin lengthwise is smaller than a second distance between the second epitaxial feature and the second gate structure along the second fin lengthwise, wherein a depth of the first epitaxial feature into the first fin is smaller than a depth of the second epitaxial feature into the second fin.