SiO{sub x} layer formation during plasma sputtering of Si and SiO{sub 2} targets

• Published in: Semiconductors (Woodbury, N.Y.) Vol. 42; no. 6
• Main Authors: Karpov, A. N., Marin, D. V., Volodin, V. A., Jedrzejewski, J., Kachurin, G. A., Savir, E., Shwartz, N. L., Yanovitskaya, Z. Sh, Balberg, I., Goldstein, Y.
• Format: Journal Article
• Language: English
• Published: United States 15.06.2008
• Subjects: ANNEALING; ARGON; COORDINATES; DEPOSITION; ION BEAMS; LAYERS; MATERIALS SCIENCE; NANOSTRUCTURES; OXIDATION; PHOTOLUMINESCENCE; REFRACTIVE INDEX; SILICON; SILICON OXIDES; SPUTTERING; SYNTHESIS
• DOI: 10.1134/S106378260806016X
• ISSN: 1063-7826

Deposition of SiO{sub x} layers of variable composition onto silicon wafers was performed by co-sputtering of spaced Si and SiO{sub 2} targets in argon plasma. Coordinate dependences of the thickness and refractive index of separately deposited Si and SiO{sub 2} layers and the SiO{sub x} layer grown during co-sputtering of targets were determined using optical techniques. It was shown that the SiO{sub x} layer composition is not equal to a simple sum of thicknesses of separately deposited Si and SiO{sub 2} layers. The coordinate dependences of the Si and SiO{sub 2} layer thicknesses were calculated. To fit the calculated and experimental data, it is necessary to assume that no less than 10% of silicon is converted to dioxide during co-sputtering. A comparison of the coordinate dependences of the IR absorbance in SiO{sub 2} and SiO{sub x} layers with experimental ellipsometric data confirmed the presence of excess oxygen in the SiO{sub x} layer. Taking into account such partial oxidation of sputtered silicon, composition isolines in the substrate plane were calculated. After annealing of the SiO{sub x} layer at 1200{sup o}C, photoluminescence was observed in a wafer area predicted by calculations, which was caused by the formation of quantum-size Si nanocrystallites. The photoluminescence intensity was maximum at x = 1.78 {+-} 0.3, which is close to the composition optimum for ion-beam synthesis of nanocrystals.