Semiconductor device and method

A method comprising:

• forming a gate stack on sidewalls and a top surface of a semiconductor fin;
• and
• forming source/drain regions on opposite sides of the gate stack, wherein forming each of the source/drain regions comprises:
• performing a first etching process to etch the semiconductor fin in a vertical direction and form a first source/drain recess;
• performing a second etching process to etch the semiconductor fin in a vertical direction and a horizontal direction to extend the first source/drain recess, wherein the second etching process continues until etchants of the second etching process are exposed to surfaces of the semiconductor fin that are in the (110) family of crystallographic planes;
• and
• epitaxially growing a semiconductor material in the first source/drain recess.

A device comprising:

• a channel region over a first semiconductor strip;
• a gate stack over sidewalls and a top surface of the channel region, wherein the channel region comprises:
• a first portion having a first width;
• and
• a second portion under the first portion and having a second width, wherein the second width is smaller than the first width;
• and
• a source/drain region on a side of the channel region, wherein at an interface between the source/drain region and the second portion of the channel region, surfaces of the second portion of the channel region are in the (110) family of crystallographic planes.