FinFETs having strained channels, and methods of fabricating finFETs having strained channels
First Claim
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1. A method for forming fins of a finFET, the method comprising:
- forming one or more spacer layers over a fin including a semiconductor fin having a first height;
forming a planarized layer over the one or more spacer layers, the planarized layer being etch selective relating to the spacer layers;
recessing the planarized layer to a level between a bottom of the semiconductor fin and a top of the semiconductor fin;
etching the one or more spacer layers in a region adjacent the fin to expose at least a portion of the fin above a second height that is less than the first height, said etching of the one or more spacer layers being self-limited at the second height by the level of the recessed planarized layer;
removing the recessed planarized layer; and
etching the exposed portion of the fin to remove a portion of the semiconductor fin to a height determined, at least in part, by a top surface of the previously etched at least one of the one or more spacer layers at the second height.
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Abstract
Techniques and structures for controlling etch-back of a finFET fin are described. One or more layers may be deposited over the fin and etched. Etch-back of a planarization layer may be used to determine a self-limited etch height of one or more layers adjacent the fin and a self-limited etch height of the fin. Strain-inducing material may be formed at regions of the etched fin to induce strain in the channel of a finFET.
65 Citations
21 Claims
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1. A method for forming fins of a finFET, the method comprising:
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forming one or more spacer layers over a fin including a semiconductor fin having a first height; forming a planarized layer over the one or more spacer layers, the planarized layer being etch selective relating to the spacer layers; recessing the planarized layer to a level between a bottom of the semiconductor fin and a top of the semiconductor fin; etching the one or more spacer layers in a region adjacent the fin to expose at least a portion of the fin above a second height that is less than the first height, said etching of the one or more spacer layers being self-limited at the second height by the level of the recessed planarized layer; removing the recessed planarized layer; and etching the exposed portion of the fin to remove a portion of the semiconductor fin to a height determined, at least in part, by a top surface of the previously etched at least one of the one or more spacer layers at the second height. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method for forming a finFET, comprising:
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forming a fin structure including a semiconductor fin formed from a semiconductor layer of a silicon on insulator substrate, wherein the fin structure has a first fin height; forming a gate structure over a channel region of the fin structure; forming a spacer layer over the gate structure and the fin structure; forming a planarized layer over the spacer layer, the planarized layer being etch selective relative to the spacer layer; recessing the planarized layer to a top surface at a level between a bottom of the fin structure and a top of the fin structure; etching the spacer layer to expose an upper portion of the fin structure, said etching of the spacer layer using the top surface of the recessed planarizing layer to self-limit the etching of the spacer layer to stop at a level approximately at a top surface of the spacer layer adjacent to the fin structure; removing the planarizing layer; etching the semiconductor fin of the fin structure to reduce the fin structure to a second fin height, the second fin height being less than the first fin height, so that sides of a lower portion of the fin structure remain covered by the etched spacer layer, said etching of the semiconductor fin using said etched spacer layer to self-limit the etching of the fin structure to stop at a level approximately at the top surface of the spacer layer; wherein a channel region of the fin structure remains at the first fin height under the gate structure; and epitaxially growing a source region and a drain region on exposed surfaces of the etched semiconductor fin adjacent the channel region. - View Dependent Claims (18, 19, 20, 21)
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Specification