FT IR spectroscopy of silicon oxide layers prepared with perchloric acid

• Published in: Applied surface science Vol. 269; pp. 106 - 109
• Main Authors: Kopani, M., Mikula, M., Takahashi, M., Rusnák, J., Pinčík, E.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15-03-2013; Elsevier
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Infrared and Raman spectra; Infrared and raman spectra and scattering; Infrared spectroscopy; KCN treatment; Materials science; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Passivation; Perchloric acid; Physics; Silicon oxide; Surface treatments; Silicon oxide; Infrared spectroscopy; KCN treatment; Perchloric acid; Passivation; Inorganic compounds; Chlorine; Mechanical strength; Minority carriers; Infrared spectra; Thickness; Silicon oxides; Carrier lifetime; Capacitance; Fourier transform spectra; Oxidation; Silicon; X-ray photoelectron spectra
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2012.09.081

► Formation of stoichiometric SiO2 layer with lowest density after chlorine oxidation ► KCN/HCN passivation contributes to formation of SiN, SiO and SiOH bonds at the expense of SiCl bonds. ► SiCN could not be identified due to overlapping of detected signal with absorption induced by CO2.
Chlorine oxidation is important methods for improvement of many properties such as passivation of mobile oxide charge, breakdown strength or enhancement of the minority-carrier lifetime in the underlying silicon. In this study we consider effects influencing the density of SiO2 layers formed by three different methods: thermal oxidation at 850°C, low temperature oxidation method by use of nitric acid – HNO3 (NAOS) and HClO4 afterward passivated with KCN/HCN solutions. Thicknesses of SiO2 layers determined by both capacitance–voltage (C–V) and XPS revealed fast oxidation rate compared with samples prepared by thermal oxidation. FT IR measurement showed that all absorption spectra are almost similar. Higher absorption of the sample prepared in HClO4 was observed. No SiCl bonds were visible. Calculated atomic density of the SiO2 layer obtained from IR measurements was lowest for sample formed in HClO4. Chlorine oxidation results in higher oxidation rate (higher thickness) and formation of stoichiometric SiO2 layer with lower density. Following KCN/HCN passivation causes formation of SiN, SiO and SiOH bonds at the expense of SiCl bonds.