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US 12,733,198 B2Granted
Semiconductor device and method of manufacture
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsLi-Li Su, Wei-Min Liu, Wei Hao Lu, Chien-I Kuo, Yee-Chia Yeo
Life of this patent
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Abstract
A device includes a fin extending from a substrate; a gate stack over and along sidewalls of the fin; a gate spacer along a sidewall of the gate stack; an epitaxial source/drain region in the fin and adjacent the gate spacer, the epitaxial source/drain region including a first epitaxial layer on the fin, the first epitaxial layer including silicon and arsenic; and a second epitaxial layer on the first epitaxial layer, the second epitaxial layer including silicon and phosphorus, the first epitaxial layer separating the second epitaxial layer from the fin; and a contact plug on the second epitaxial layer.
Claims20
A method comprising:
- depositing a dummy gate over and along sidewalls of a fin extending upwards from a substrate;
- forming a gate spacer along a sidewall of the dummy gate;
- forming a recess in the fin adjacent the gate spacer;
- and
- forming a source/drain region in the recess, the forming of the source/drain region comprising:
- epitaxially growing a first doped silicon layer lining the recess, wherein the first doped silicon layer is doped with arsenic, wherein portions of the first doped silicon layer near a top of the recess have a first thickness, wherein portions of the first doped silicon layer near a bottom of the recess have a second thickness that is greater than the first thickness;
- and
- epitaxially growing a second doped silicon layer on the first doped silicon layer, wherein the second doped silicon layer is doped with phosphorus, and wherein the source/drain region has a doping transition length in a range of 7 nm to 15 nm, wherein the doping transition length is defined as a distance from an interface between the source/drain region and a channel region to a position in the channel region at which a total dopant concentration is less than 1E1018 atoms/cm3.
5 more elements
A method comprising:
- etching a recess in a semiconductor fin, wherein the recess is adjacent a channel region of the semiconductor fin;
- and
- forming a source/drain region in the recess and having a doping transition length in a range of 7 nm to 15 nm, wherein the doping transition length is defined as a distance from an interface between the source/drain region and the channel region to a position in the channel region at which a total dopant concentration is less than 1E1018 atoms/cm3, wherein forming the source/drain region comprises:
- performing a first epitaxial growth process to form a first epitaxial layer on surfaces of the recess, wherein the first epitaxial layer comprises a first n-type dopant, wherein the first epitaxial layer has a region of maximum concentration of the first n-type dopant that is separated from upper surfaces of the first epitaxial layer by a nonzero first distance;
- performing a second epitaxial growth process to form a second epitaxial layer on the first epitaxial layer, wherein the second epitaxial layer comprises a second n-type dopant that has a larger diffusivity than the first n-type dopant, the second epitaxial growth process does not use any precursor that comprises the first n-type dopant to form the second epitaxial layer;
- and
- after performing the second epitaxial growth process, diffusing the first n-type dopant from the first epitaxial layer into the second epitaxial layer.
4 more elements
A method comprising:
- forming a fin protruding from a semiconductor substrate;
- forming a source/drain region in the fin, comprising:
- forming a recess in the fin, wherein the recess is U-shaped;
- forming a conformal layer of arsenic-doped silicon in the recess, wherein the conformal layer of arsenic-doped silicon has a thickness in a range of 1 nm to 12 nm;
- and
- filling remaining portions of the recess with phosphorus-doped silicon, wherein the maximum concentration of phosphorus in the phosphorus-doped silicon is greater than the maximum concentration of arsenic in the conformal layer of arsenic doped silicon, wherein the phosphorus-doped silicon comprises arsenic, and wherein a concentration of phosphorus in the phosphorus-doped silicon is greater than a concentration of arsenic in the phosphorus-doped silicon;
- and
- forming a contact plug protruding into the phosphorus-doped silicon, wherein the contact plug is separated from the conformal layer of arsenic-doped silicon, wherein the source/drain region has a doping transition length in a range of 7 nm to 15 nm, and wherein the doping transition length is defined as a distance from an interface between the source/drain region and a channel region to a position in the channel region at which a total dopant concentration is less than 1E1018 atoms/cm3.
5 more elements
Dependencies are inferred from the claim text.