Composite stressors with variable element atomic concentrations in MOS devices
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorYin-Ping Wang
Life of this patent
Estimating the term…
Abstract
A semiconductor device includes a semiconductor substrate, a gate stack on the semiconductor substrate, and a stressor adjacent the gate stack and having at least a portion in the semiconductor substrate, wherein the stressor comprises an element for adjusting a lattice constant of the stressor. The stressor includes a lower portion and a higher portion on the lower portion, wherein the element in the lower portion has a first atomic percentage, and the element in the higher portion has a second atomic percentage substantially greater than the first atomic percentage.
Claims20
A semiconductor device comprising:
- a semiconductor substrate;
- a gate stack on the semiconductor substrate;
- and
- a stressor adjacent the gate stack and having at least a portion in the semiconductor substrate, wherein the stressor comprises an element selected from the group consisting essentially of germanium and carbon and having a lattice constant different from a lattice constant of the semiconductor substrate, and wherein the stressor comprises:
- a lower portion comprising the element, wherein the element in the lower portion has a first atomic percentage;
- and
- a higher portion on the lower portion, wherein the element in the higher portion has a second atomic percentage substantially greater than the first atomic percentage, wherein an interface between the lower portion and the higher portion of the stressor comprises a first portion and a second portion, and wherein the first portion is between a bottom of the higher portion and a top of the lower portion of the stressor, and the second portion is between sidewalls of the higher and the lower portions of the stressor.
A semiconductor device comprising:
- a semiconductor substrate comprising silicon;
- a gate stack on the semiconductor substrate;
- a stressor region adjacent the gate stack and having at least a portion in the semiconductor substrate, wherein the stressor region comprises silicon and an element selected from the group consisting essentially of germanium and carbon, and wherein the element in the stressor has a first atomic percentage;
- an intermediate region between the semiconductor substrate and the stressor region, wherein the intermediate region comprises silicon and the element, and wherein the element in the intermediate region has a second atomic percentage lower than the first atomic percentage, and greater than a third atomic percentage of the element in the semiconductor substrate;
- and
- an interface between the stressor region and the intermediate region comprises a first portion and a second portion, wherein the first portion is between a bottom of the stressor region and a top of the intermediate region, and the second portion is between sidewalls of the stressor region and the intermediate region.
Dependencies are inferred from the claim text.