Re-growing source/drain regions from un-relaxed silicon layer
First Claim
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1. A method comprising:
- forming a silicon germanium layer;
forming a silicon-containing layer over the silicon germanium layer, wherein an atomic percentage of the silicon-containing layer is lower than an atomic percentage of the silicon germanium layer;
forming a gate stack over the silicon-containing layer and the silicon germanium layer;
recessing the silicon-containing layer to form a recess adjacent the gate stack; and
epitaxially growing a silicon-containing semiconductor region in the recess to form a source/drain stressor, wherein the silicon-containing semiconductor region forms a source/drain region of an n-type metal-oxide-semiconductor (NMOS) field-effect transistor (FET).
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Abstract
A method of forming an n-type metal-oxide-semiconductor (NMOS) field-effect transistor (FET) includes forming a silicon germanium layer, and forming a silicon layer over the silicon germanium layer. A gate stack is formed over the silicon layer. The silicon layer is recessed to form a recess adjacent the gate stack. A silicon-containing semiconductor region is epitaxially grown in the recess to form a source/drain stressor, wherein the silicon-containing semiconductor region forms a source/drain region the NMOS FET.
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Citations
13 Claims
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1. A method comprising:
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forming a silicon germanium layer; forming a silicon-containing layer over the silicon germanium layer, wherein an atomic percentage of the silicon-containing layer is lower than an atomic percentage of the silicon germanium layer; forming a gate stack over the silicon-containing layer and the silicon germanium layer; recessing the silicon-containing layer to form a recess adjacent the gate stack; and epitaxially growing a silicon-containing semiconductor region in the recess to form a source/drain stressor, wherein the silicon-containing semiconductor region forms a source/drain region of an n-type metal-oxide-semiconductor (NMOS) field-effect transistor (FET). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method comprising:
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epitaxially growing a silicon germanium layer over a portion of a silicon substrate; epitaxially growing a silicon layer over the silicon germanium layer, wherein the silicon germanium layer is relaxed, and the silicon layer is un-relaxed; forming a gate stack over the silicon layer and the silicon germanium layer, wherein a portion of the silicon layer forms a channel region of an n-type metal-oxide-semiconductor (NMOS) field-effect transistor (FET); recessing the silicon layer to form recesses on opposite sides of the gate stack; and epitaxially growing silicon germanium stressors in the recesses, wherein the silicon germanium stressors have a germanium atomic percent lower than a germanium atomic percent of the silicon germanium layer, and wherein the silicon germanium stressors form source and drain regions of the NMOS FET. - View Dependent Claims (10, 11, 12, 13)
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Specification