Growth of SiO 2 films by TEOS-PECVD system for microelectronics applications

Abstract

Silicon dioxide (SiO 2) films have been grown by a plasma enhanced chemical vapor deposition (PECVD) system using liquid tetraethoxysilane (TEOS) as a source of Si instead of hazardous silane gas. The effect of variation in the RF power on the properties of the deposited SiO 2 films, at constant chamber pressure of 133 Pa have been studied. However, the other process parameters such as substrate temperature, TEOS bubbler temperature, inter-electrode spacing and process time are kept at their optimized constant values of 300 °C, 45 °C, 8 cm and 5 min, respectively. The ellipsometric observations for growth rate, refractive index (RI) and stress of the SiO 2 film have been reported. Thickness uniformity within the substrate and substrate-to-substrate has been observed for deposited SiO 2 films. The films have been etched with standard etchants and an etch rate of approximately 313 nm/min has been observed. The dependence of etch rate on RF power, refractive index, stress has been depicted. The transmittance spectra of the deposited SiO 2 films have also been taken by using Fourier transform infrared (FTIR) spectroscopy and the spectra observed to be qualitatively same for the SiO 2 films deposited at different RF powers. It is found that the SiO 2 films deposited at lower RF power possess better optical, mechanical, chemical properties suitable for microelectronics applications.