Comparative study of Si precipitation in silicon-rich oxide films

Two techniques often used in semiconductor industry, namely, low-pressure chemical vapour deposition (LPCVD) and plasma enhanced chemical vapour deposition (PECVD), were used to deposit silicon-rich oxide layers. Thermal treatments have been performed to promote Si precipitation. The composition of the layers was monitored by X-ray photoelectron spectroscopy showing significant nitrogen content (∼8%) only in PECVD layers. The formation of Si nanoclusters has been evidenced by Raman spectroscopy and photoluminescence measurements. LPCVD layers revealed a precipitation even in the as deposited films, and a phase separation was achieved at View the MathML source, while the clusters remain amorphous for PECVD grown films. Electron images of the films revealed an average size of the Si clusters of 3–5 nm with a density around View the MathML source. The optimum temperature for a strong near-infrared emission from Si precipitates was found around View the MathML source for LPCVD and View the MathML source for PECVD layers.