Growth of SiO2 films by TEOS-PECVD system for microelectronics applications

Silicon dioxide (SiO2) 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 SiO2 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 SiO2 film have been reported. Thickness uniformity within the substrate and substrate-to-substrate has been observed for deposited SiO2 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 SiO2 films have also been taken by using Fourier transform infrared (FTIR) spectroscopy and the spectra observed to be qualitatively same for the SiO2 films deposited at different RF powers. It is found that the SiO2 films deposited at lower RF power possess better optical, mechanical, chemical properties suitable for microelectronics applications.