Dissociation of Si{sup +} ion implanted and as-grown thin SiO{sub 2} layers during annealing in ultra-pure neutral ambient by emanation of SiO
- Forschungszentrum Dresden--Rossendorf, Institute of Ion Beam Physics and Materials Research, P.O. Box 51 01 19, D-01314 Dresden (Germany)
We have observed a very inhomogeneous dissociation of stoichiometric and non-stoichiometric thin SiO{sub 2} layers (thermally grown on Si substrates) during high temperature annealing at a low partial pressure of oxygen. During this process some silicon of the (100)Si substrate and, in case of Si ion implantation, and additionally, excess Si is consumed. The SiO{sub 2} dissociation has been studied by electron microscopy and Rutherford backscattering spectrometry. Large holes (>1 {mu}m) in non-implanted oxide layers have been observed which evolve probably from defects located at the Si/SiO{sub 2} interface. For Si implanted SiO{sub 2} additionally the formation of voids within the oxide during annealing has been observed preferably at the position of the implanted Si excess. Oxygen vacancies are possibly emitted from Si/SiO{sub 2} interfaces into the oxide and migrate through SiO{sub 2} with long-range distortions of the oxide network. In that way the hole and void formation in the oxide can be explained by oxygen-vacancy formation, migration and silicon-monoxide (SiO) emanation. As a driving force for growth of the large holes we identified oxygen diffusion from the Si/SiO{sub 2} interface to the bare Si surface. This surface is a sink of oxygen diffusion due to the emanation of volatile SiO, whereas the Si/SiO{sub 2} interface serves as an oxygen source. The predicted mechanism is consistent with the geometry of the holes in the SiO{sub 2} layer.
- OSTI ID:
- 20982726
- Journal Information:
- Journal of Applied Physics, Vol. 101, Issue 5; Other Information: DOI: 10.1063/1.2436834; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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