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The Physics of Non–Equilibrium Reliability Phenomena

Appendices

Chapter A Structural Properties of Si/SiO\(_2\) Models

A.1 Geometrical Characterization

In order to properly assess the quality of the utilized Si/\(a\)–SiO\(_2\)/Si interface models, an analysis provides information of the geometrical and structural properties of the three atomistic models. The four panels in Fig. A.1 show the Si–O–Si and O–Si–O angle distribution within the structures as well as a function of their position across the structures. Particularly at the interfaces to \(c\)–Si, the O–Si–O angles show a compressed distribution compared to bulk SiO\(_2\) which can be attributed to the lattice mismatch and the resulting compressive stress.

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Figure A.1: O–Si–O (Upper) and Si–O–Si (Lower) angle distribution within the utilized interface models. The data are shown as a histogram (Left) and as a function of their position across the structure (Right).

The Si–O and Si–Si bond length distributions are shown in the four panels of Fig. A.2. One can again clearly see that within the direct vicinity of the interfacial regions Si–O and also Si–Si bonds tend to be more stretched and compressed, respectively. Note that the Si–Si nearest neighbour distance actually shows a bimodal distribution; one for the bond lengths in the Si substrate and the other one for the nearest Si neighbours in the amorphous SiO\(_2\) layers.

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Figure A.2: Si–O (Upper) and Si–Si (Lower) bond length distribution within the utilized interface models. The data are shown as a histogram (Left) and as a function of their position across the structure (Right).