Structure and method to improve channel mobility by gate electrode stress modification
First Claim
1. A method of adjusting carrier mobility in semiconductor devices comprising the steps ofdepositing a metal or combination of metals to contact one of a first or second transistor gate structure, wherein said depositing step comprisesdepositing a first metal or combination of metals to a portion of gate electrode material in said first or second transistor structure to form an alloy at the lower region of the gate electrode proximate to the channel of said first or second transistor;
- anddepositing a second metal or combination of metals over said first or second transistor gate electrode to form a first stressed alloy within said first or second transistor gate in the upper region of the gate electrode, andalloying said metal or combination of metals and said one of a first and second transistor gate structure to form at least said first stressed alloy within said one of a first or second transistor gate whereby a first stress is created in at least one corresponding channel of first or second transistors without producing a stress in a channel of the other transistor of said first or second transistors.
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Abstract
In producing complementary sets of metal-oxide-semiconductor (CMOS) field effect transistors, including nFET and pFET), carrier mobility is enhanced or otherwise regulated through the reacting the material of the gate electrode with a metal to produce a stressed alloy (preferably CoSi2, NiSi, or PdSi) within a transistor gate. In the case of both the nFET and pFET, the inherent stress of the respective alloy results in an opposite stress on the channel of respective transistor. By maintaining opposite stresses in the nFET and pFET alloys or silicides, both types of transistors on a single chip or substrate can achieve an enhanced carrier mobility, thereby improving the performance of CMOS devices and integrated circuits.
225 Citations
5 Claims
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1. A method of adjusting carrier mobility in semiconductor devices comprising the steps of
depositing a metal or combination of metals to contact one of a first or second transistor gate structure, wherein said depositing step comprises depositing a first metal or combination of metals to a portion of gate electrode material in said first or second transistor structure to form an alloy at the lower region of the gate electrode proximate to the channel of said first or second transistor; - and
depositing a second metal or combination of metals over said first or second transistor gate electrode to form a first stressed alloy within said first or second transistor gate in the upper region of the gate electrode, and alloying said metal or combination of metals and said one of a first and second transistor gate structure to form at least said first stressed alloy within said one of a first or second transistor gate whereby a first stress is created in at least one corresponding channel of first or second transistors without producing a stress in a channel of the other transistor of said first or second transistors. - View Dependent Claims (2, 3, 4, 5)
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Specification