Ab Initio Study of Strain Effects on the Quasiparticle Bands and Effective Masses in Silicon
Using ab initio computational methods, we study the structural and electronic properties of strained silicon, which has emerged as a promising technology to improve the performance of silicon-based metal-oxide-semiconductor field-effect transistors. In particular, higher electron mobilities are obse...
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| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Wiley
2015-01-01
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| Series: | Advances in Condensed Matter Physics |
| Online Access: | http://dx.doi.org/10.1155/2015/453125 |
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| Summary: | Using ab initio computational methods, we study the structural and electronic properties of
strained silicon, which has emerged as a promising technology to improve the performance of silicon-based
metal-oxide-semiconductor field-effect transistors. In particular, higher electron mobilities
are observed in n-doped samples with monoclinic strain along the [110] direction, and experimental
evidence relates this to changes in the effective mass as well as the scattering rates. To assess the
relative importance of these two factors, we combine density-functional theory in the local-density
approximation with the GW approximation for the electronic self-energy and investigate the effect
of uniaxial and biaxial strains along the [110] direction on the structural and electronic properties of
Si. Longitudinal and transverse components of the electron effective mass as a function of the strain
are derived from fits to the quasiparticle band structure and a diagonalization of the full effective-mass
tensor. The changes in the effective masses and the energy splitting of the conduction-band
valleys for uniaxial and biaxial strains as well as their impact on the electron mobility are analyzed.
The self-energy corrections within GW lead to band gaps in excellent agreement with experimental
measurements and slightly larger effective masses than in the local-density approximation. |
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| ISSN: | 1687-8108 1687-8124 |