Method of fabricating semiconductor device

A method of fabricating a semiconductor device, the method comprising:

• forming a stack structure that includes a plurality of semiconductor patterns and a plurality of sacrificial patterns that are alternately stacked on a semiconductor substrate;
• forming a dummy gate electrode that runs across the stack structure;
• removing a portion of the stack structure that is exposed by the dummy gate electrode to form a recess region;
• forming a first source/drain pattern in the recess region;
• forming a second source/drain pattern on the first source/drain pattern;
• removing the dummy gate electrode and the sacrificial patterns to form empty spaces;
• and
• forming a gate dielectric layer and a gate electrode in the empty spaces,
• wherein forming the first source/drain pattern includes sequentially performing a selective epitaxial growth process and a reflow process.

A method of fabricating a semiconductor device, the method comprising:

• forming a stack structure that includes a plurality of semiconductor patterns and a plurality of sacrificial patterns that are alternately stacked on a semiconductor substrate;
• forming a dummy gate electrode that runs across the stack structure;
• removing a portion of the stack structure that is exposed by the dummy gate electrode to form a recess region;
• and
• forming a first source/drain pattern in the recess region,
• wherein forming the first source/drain pattern includes:
• performing a selective epitaxial growth process under a first pressure at a first temperature;
• and
• performing a reflow process under a second pressure at a second temperature,
• wherein the second pressure is less than the first pressure.