| 摘要 |
Manufacture of a semiconductor device comprises forming buried oxide film filling up second undercut in a space formed by removing silicon germanide epitaxial layer; forming a polysilicon layer on the buried oxide film filling up a space formed by removing a gate insulating film (140) and a first silicon epitaxial layer (120); and implanting an impurity into second silicon epitaxial layer (200) and polysilicon layer to form a source/drain region. Manufacture of a semiconductor device comprises (a) forming a device isolation film (130) defining an active region on a semiconductor substrate (100) having a silicon germanide (SiGe) epitaxial layer and a first Si epitaxial layer stacked on it; (b) sequentially forming a gate insulating film, a gate conductive layer, and a first chemical vapor deposited insulating film on the first Si epitaxial layer and the device isolation film; (c) patterning the first CVD insulating film and the gate conductive layer to form a gate structure having a first and a second side; (d) forming a light doped drain (LDD) region (170) on the first Si epitaxial layer at both sides of the gate structure; (e) forming a first sidewall spacer (180a) and a second sidewall spacer (180b) on the first side and the second side respectively; (f) etching a portion of the gate insulating film adjacent to the first and second sidewall spacers to expose a portion of the first Si epitaxial layer; (g) etching the exposed portion of the first Si epitaxial layer to expose a portion of the SiGe epitaxial layer; (h) etching the SiGe epitaxial layer adjacent to the first side and a predetermined thickness of the semiconductor substrate, where SiGe epitaxial layer is partially etched to form a first undercut under the first Si epitaxial layer; (i) forming a second Si epitaxial layer in a space including the first undercut, where second Si epitaxial layer at least fills up the first undercut; (j) performing an etching process to expose the SiGe epitaxial layer adjacent to the second side; (k) etching the exposed SiGe epitaxial layer, where SiGe epitaxial layer is removed to form a second undercut under the first Si epitaxial layer; (l) forming a buried oxide film filling up the second undercut in a space formed by removing the SiGe epitaxial layer; (m) forming a polysilicon layer on the buried oxide film filling up a space formed by removing the gate insulating film and the first Si epitaxial layer; and (n) implanting an impurity into the second Si epitaxial layer and the polysilicon layer to form a source/drain region. |
