Structure, defects, and strain in silicon-silicon oxide interfaces

Kovačević, Goran; Pivac, Branko (2014) Structure, defects, and strain in silicon-silicon oxide interfaces. Journal of Applied Physics, 115 . 043531. ISSN 0021-8979

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Abstract

The structure of the interfaces between silicon and silicon-oxide is responsible for proper functioning of MOSFET devices while defects in the interface can deteriorate this function and lead to their failure. In this paper we modeled this interface and characterized its defects and strain. MD simulations were used for reconstructing interfaces into a thermodynamically stable configuration. In all modeled interfaces, defects were found in the form of three-coordinated silicon atom, five coordinated silicon atom, threefold-coordinated oxygen atom, or displaced oxygen atom. Three-coordinated oxygen atom can be created if dangling bonds on silicon are close enough. The structure and stability of three-coordinated silicon atoms (Pb defect) depend on the charge as well as on the electric field across the interface. The negatively charged Pb defect is the most stable one, but the electric field resulting from the interface reduces that stability. Interfaces with large differences in periodic constants of silicon and silicon oxide can be stabilized by buckling of silicon layer. The mechanical stress resulted from the interface between silicon and silicon oxide is greater in the silicon oxide layer. Ab initio modeling of clusters representing silicon and silicon oxide shows about three time larger susceptibility to strain in silicon oxide than in silicon if exposed to the same deformation.

Item Type:	Article
Uncontrolled Keywords:	Silicon; silicon oxide; interface; defect; strain
Subjects:	NATURAL SCIENCES > Physics > Atomic and Molecular Physics NATURAL SCIENCES > Physics > Condensed Matter Physics NATURAL SCIENCES > Chemistry > Theoretical Chemistry
Divisions:	Division of Physical Chemistry
Depositing User:	Goran Kovačević
Date Deposited:	06 May 2015 10:34
URI:	http://fulir.irb.hr/id/eprint/1904
DOI:	10.1063/1.4862809

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