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US 9,887,290 B2Granted
Silicon germanium source/drain regions
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsJi-Yin Tsai, Yao-Tsung Huang, Chih-Hsin Ko, Clement Hsingjen Wann
Life of this patent
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Abstract
A method includes forming a gate stack over a semiconductor region, and recessing the semiconductor region 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. Arsenic is in-situ doped during the step of epitaxially growing the silicon-containing semiconductor region.
Claims19
A structure comprising:
- isolation regions extending into a semiconductor substrate;
- a semiconductor region between opposite portions of the isolation regions, wherein the semiconductor region comprises a portion extending to lower than top surfaces of the isolation regions, and the semiconductor region comprises:
- a first silicon germanium layer having a first germanium concentration;
- and
- a second silicon germanium layer over the first silicon germanium layer, wherein the second silicon germanium layer has a second germanium concentration lower than the first germanium concentration;
- a gate stack over the second silicon germanium layer;
- a source/drain region connected to an end of the semiconductor region, wherein the source/drain region comprises a silicon germanium stressor having a third germanium concentration greater than zero and lower than the first germanium concentration and the second germanium concentration, the silicon germanium stressor having a top surface protruding over a first topmost surface of the second silicon germanium layer and a second topmost surface of the isolation regions, a first sidewall of the silicon germanium stressor contacting a sidewall of the gate stack;
- and
- an etch stop layer disposed over the gate stack, the silicon germanium stressor, and the isolation regions, a second sidewall of the silicon germanium stressor contacting the etch stop layer.
6 more elements
A structure comprising:
- isolation regions in a silicon substrate;
- a first silicon germanium layer over and in contact with a portion of the silicon substrate, wherein the first silicon germanium layer has a first germanium concentration, a topmost surface of the first silicon germanium layer being lower than a topmost surface of each of the isolation regions, a bottom surface of the first silicon germanium layer being higher than a lowermost surface of each of the isolation regions;
- a second silicon germanium layer over and in contact with the first silicon germanium layer, wherein the second silicon germanium layer has a second germanium concentration lower than the first germanium concentration, a top portion of the second silicon germanium layer protruding over a top surface of the isolation regions, a bottom portion of the second silicon germanium layer being lower than the top surface of the isolation regions;
- a gate stack over the second silicon germanium layer, wherein a portion of the second silicon germanium layer forms a channel region of an n-type metal-oxide-semiconductor (NMOS) field-effect transistor (FET), the gate stack comprising a first portion directly over the second silicon germanium layer, and a second portion being on a sidewall of the top portion of the second silicon germanium layer;
- and
- semiconductor stressors on opposite sides of the gate stack, wherein the semiconductor stressors comprise silicon germanium having a third germanium concentration greater than zero and lower than both the first germanium concentration and the second germanium concentration.
3 more elements
A structure comprising:
- isolation regions extending into a silicon substrate;
- a semiconductor region between opposite portions of the isolation regions, wherein the semiconductor region comprises a portion extending to lower than top surfaces of the isolation regions, and the semiconductor region comprises:
- a first silicon germanium layer having a first germanium concentration, a top surface of the first silicon germanium layer being lower than an uppermost surface of the isolation regions, a bottom surface of the first silicon germanium layer being higher than a lowermost surface of the isolation regions;
- and
- a second silicon germanium layer over the first silicon germanium layer, wherein the second silicon germanium layer has a second germanium concentration lower than the first germanium concentration, wherein a top portion of the second silicon germanium layer protrudes over top surfaces of the isolation regions;
- a gate stack on a top surface and sidewalls of the top portion of the second silicon germanium layer;
- and
- source/drain regions on opposite sides of the gate stack, wherein the source/drain regions penetrate through the second silicon germanium layer and extends into a top portion of the first silicon germanium layer, and the source/drain regions comprise silicon germanium having a third germanium concentration greater than zero and lower than both the first germanium concentration and the second germanium concentration.
5 more elements
Dependencies are inferred from the claim text.