1. Thermal oxidation of Si (001) single crystal implanted with Ge ions.
- Author
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Terrasi, A., Scalese, S., Re, M., Rimini, E., Iacona, F., Raineri, V., La Via, F., Colonna, S., and Mobilio, S.
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CRYSTALS , *OXIDATION - Abstract
The thermal oxidation of Ge-implanted Si single crystals has been investigated for different Ge doses (3 × l0[sup 15] cm[sup -2] and 3 × 10[sup 16] cm[sup -2]) and different oxidation processes (in wet ambient at 920 °C for 30, 60, and 120 min, or dry ambient at ll00 °C for 30 min). The oxide roughness, the oxidation rate, the Ge diffusion, precipitation, and clustering, have been monitored by several experimental techniques: atomic force microscopy, transmission electron microscopy, Rutherford backscattering spectrometry, and x-ray absorption spectroscopy. We found that the surface roughness is related to the segregation of Ge at the oxide/substrate interface, occurring when the oxidation rate is faster than the Ge diffusion, in particular at the higher implanted dose (3 × 10[sup 16] cm[sup -2]) when processed in a wet ambient. For these conditions, we also observed an oxidation rate enhancement with respect to pure Si, and a strong indication that pure Ge clusters were formed. When a critical Ge concentration at the interface is reached, the oxidation mechanisms change and the oxidation rate is reduced, along with Ge diffusion into the substrate and a consequent reduction of the Ge fraction at the interface. Nevertheless, the oxide roughness still increases despite the Ge concentration reduction, resulting from the initial nucleation of precipitates. [ABSTRACT FROM AUTHOR]
- Published
- 2002
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