1. A first principles study on tunneling current through Si/SiO2/Si structures
- Author
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Hideaki Tsuchiya, Matsuto Ogawa, and Yoshihiro Yamada
- Subjects
Materials science ,Silicon ,Condensed matter physics ,Transistor ,Scanning tunneling spectroscopy ,Oxide ,General Physics and Astronomy ,chemistry.chemical_element ,law.invention ,chemistry.chemical_compound ,chemistry ,law ,MOSFET ,Density functional theory ,Electronic band structure ,Quantum tunnelling - Abstract
In this paper, we study tunneling current properties through SiO2 gate oxides in Si metal-oxide-semiconductor field-effect transistors (MOSFETs) by applying a first principles method based on the density-functional theory and nonequilibrium Green’s function approach. We employed three structural models of SiO2 layers, which are β-quartz, β-cristobalite, and β-tridymite. As a result, we found that the β-cristobalite and β-tridymite models indicate similar tunneling current properties, while the β-quartz model predicts a substantially lower tunneling current. Further, the largest tunneling current is obtained for the β-tridymite SiO2 model, which is consistent with bandstructure parameters estimated for bulk SiO2 crystals. Therefore, electronic properties of bulk SiO2 crystals can still be important for tunneling current analysis in the nanoscale range of oxide thickness.
- Published
- 2009