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US 8,709,897 B2Granted
High performance strained source-drain structure and method of fabricating the same
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsHsueh-Chang Sung, Ming-Huan Tsai, Hsien-Hsin Lin, Chun-Fai Cheng, Wei-Han Fan
Life of this patent
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Abstract
A method for forming a high performance strained source-drain structure includes forming a gate structure on a substrate and forming a pocket implant region proximate to the gate structure. Spacers are formed adjacent to the gate structure. A dry etch forms a recess with a first contour; a wet etch enlarge the recess to a second contour; and a thermal etch enlarges the recess to a third contour. The source-drain structure is then formed in the recess having the third contour.
Claims20
A method comprising:
- providing a semiconductor substrate;
- forming a gate structure on the semiconductor substrate;
- forming a pocket implant region proximate to the gate structure including a portion that is directly below the gate structure and physically contacting a dielectric layer of the gate structure, wherein after forming the pocket implant region a portion of the semiconductor substrate forming a channel of the gate structure physically contacts the dielectric layer of the gate structure and is free of the pocket implant region;
- forming spacers adjacent to the gate structure;
- performing a dry etch to form a recess with a first contour;
- performing a wet etch to enlarge the recess to a second contour;
- performing a thermal etch to enlarge the recess to a third contour, wherein performing the thermal etch to enlarge the recess to the third contour includes completely removing the portion of the pocket implant region that is directly below the gate structure and physically contacting the dielectric layer of the gate structure, wherein after performing the thermal etch to enlarge the recess to the third contour the portion of the substrate forming the channel of the gate structure physicall contacts the dielectric layer of the gate structure;
- forming a source-drain structure in the recess having the third contour;
- and
- wherein the dry etch, the wet etch, and the thermal etch are performed without a light doped drain (LDD) implantation process having been previously performed to form a LDD feature in the substrate proximate the gate structure.
7 more elements
A method comprising:
- providing a substrate with a gate structure;
- forming a pocket implant region proximate to the gate structure including a portion that is directly below the gate structure and physically contacting a dielectric layer of the gate structure, wherein after forming the pocket implant region a portion of the substrate forming a channel of the gate structure physically contacts the dielectric layer of the gate structure and is free of the pocket implant region;
- forming spacers adjacent to and on either side of the gate structure to overlie the pocket implant region;
- performing a dry etch on the substrate to form a recess with a first contour in the pocket implant region;
- performing a wet etch on the recess to enlarge the recess to a second contour;
- performing a thermal etch on the enlarged recess to enlarge the enlarged recess to a third contour, wherein performing the thermal etch on the enlarged recess to enlarge the enlarged recess to the third contour includes completely removing the portion of the pocket implant region that is directly below the gate structure and physically contacting the dielectric layer of the gate structure, wherein after performing the thermal etch the portion of the substrate forming the channel of the gate structure physically contacts the dielectric layer of the gate structure;
- and
- forming a source-drain structure in the enlarged recess having the third contour by depositing a semiconductor material including Silicon-Germanium (SiGe).
5 more elements
A method comprising:
- forming a gate structure on a substrate;
- forming a pocket implant region proximate to the gate structure including a portion that is directly below the gate structure and physically contacting a dielectric layer of the gate structure, wherein after forming the pocket implant region a portion of the substrate forming a channel of the gate structure physically contacts the dielectric layer of the gate structure and is free of the pocket implant region;
- performing a first etch to form a recess with a first contour;
- performing a second etch to enlarge the recess to a second contour
- performing a third etch to enlarge the recess to a third contour, wherein performing the third etch to enlarge the recess to the third contour includes completely removing the portion of the pocket implant region that is directly below the gate structure and physically contracting the dielectric layer of the gate structure, wherein after performing the third etch the portion of the substrate forming the channel of the gate structure physically contacts the dielectric layer of the gate structure;
- and
- forming a source-drain structure in the recess having the third contour,
- wherein the first, second, and third etch are different from each other.
5 more elements
Dependencies are inferred from the claim text.