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US 9,755,051 B2Granted
Embedded shape sige for strained channel transistors
AssigneeSTMicroelectronics S.r.l.
InventorsJohn H. Zhang, Pietro Montanini
Life of this patent
Estimating the term…
Abstract
An integrated circuit die includes a silicon substrate. PMOS and NMOS transistors are formed on the silicon substrate. The carrier mobilities of the PMOS and NMOS transistors are increased by introducing tensile stress into the channel regions of the NMOS transistors and compressive stress into the channel regions of the PMOS transistors. Tensile stress is introduced by including a region of SiGe below the channel region of the NMOS transistors. Compressive stress is introduced by including regions of SiGe in the source and drain regions of the PMOS transistors.
Claims24
A method, comprising:
- forming a source region by implanting dopants into a substrate;
- forming a drain region by implanting dopants into the substrate, the source and drain regions separated by a channel region of the substrate;
- forming in the source region a first trench in the substrate, the first trench having angled sides extending below a lowermost boundary of the source region and converging toward a tip in the substrate, an outermost boundary of the angled sides of the first trench being above the lowermost boundary of the source region;
- forming in the drain region a second trench in the substrate, the second trench having angled sides extending below a lowermost boundary of the drain region and converging toward a tip in the substrate, an outermost boundary of the angled sides of the second trench being above the lowermost boundary of the drain region;
- inducing strain on the channel region by filling the first and second trenches with a strain inducing material;
- and
- forming a gate structure over the channel region.
4 more elements
A method, comprising:
- implanting dopants into a silicon substrate to a first selected depth to form an n-type source region in the silicon substrate;
- implanting dopants into the silicon substrate to a second selected depth to form an n-type drain region in the silicon substrate;
- forming in the silicon substrate, between the n-type source and drain regions, a trench having substantially straight sides and extending downward into the silicon substrate to a depth below the first selected depth and below the second selected depth;
- filling the trench with SiGe;
- and
- forming a metal gate structure directly over the trench.
3 more elements
A method, comprising:
- forming in a substrate a compressively-strained PMOS transistor having a gate, a p-type source, and a p-type drain, the p-type source and drain including a pair of SiGe regions embedded fully below a top surface of the substrate and having angled sides, each one of the pair of SiGe regions extending below a lowermost boundary of the p-type source and drain regions and converging toward a tip in the substrate;
- forming in the substrate a tensilely strained NMOS transistor having a gate, an n-type source, an n-type drain, and an n-type silicon channel, the gate of the PMOS transistor having an additional layer that is not included in the gate of the NMOS transistor, the n-type source and drain spaced apart by a single SiGe region embedded fully below the top surface, the single SiGe region having substantially straight sides oriented transverse to the top surface, the n-type silicon channel formed on the single SiGe region;
- and
- forming between the compressively-strained PMOS transistor and the tensilely strained NMOS transistor an isolation region filled with an insulating material.
1 more element
A method, comprising:
- forming a first source region, a second source region, a first drain region, and a second drain re ion in a substrate;
- forming a first trench and a second trench in the first source region and the first drain region, respectively, the first trench and the second trench each having a non-rectangular shape;
- forming a third trench in the substrate and between the second source region and the second drain region, the third trench having a rectangular shape:
- filling the first trench, the second trench, and the third trench with a stress inducing material;
- and
- forming, subsequent to filling the first trench and the second trench, a first gate structure on the substrate between the first trench and the second trench;
- and
- forming a second gate structure directly over the third trench.
5 more elements
Dependencies are inferred from the claim text.