Deposition of Microcrystalline Si1-xGex by RF Magnetron Sputtering on SiO2 Substrates

概要

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Microcrystalline Si1-xGex ($x\sim 0.8$) films have been deposited by magnetron sputtering on SiO2 substrates. Crystallinity was evaluated by spectroscopic ellipsometry, Raman scattering, X-ray diffraction (XRD), transmission electron microscopy (TEM), and electron backscatter diffraction (EBSD). Detailed investigation of the deposition behavior revealed that crystalline phase begins to form at 300 °C, which roughly corresponds to half of the melting temperature of the material. At 300 °C, crystallinity changes with thickness, i.e., crystallinity improves as thickness increases. It was found out that this change in the crystallinity is not due to the heat up of the substrate, but is an essential phenomenon. At 350 °C, on the other hand, crystalline phase is formed almost from the beginning of the deposition. However, surface (${<}100$ nm) crystallinity of the 300 °C sample is higher compared with 350 °C sample when the film thickness is more than 500 nm. Substrate bias effect was also investigated. Crystallinity of 300 °C sample improves while that of 350 °C sample degrades when RF bias power is applied to the substrate.
2009-04-25