Characteristics of SiOF Films Formed Using Tetraethylorthosilicate and Fluorotriethoxysilane at Room Temperature by Chemical Vapor Deposition

Abstract

The characteristics of SiOF films deposited using tetraethylorthosilicate (TEOS) and fluorotriethoxysilane at room temperature by chemical vapor deposition (RTCVD) have been studied. The RTCVD technique utilizes FTES, TEOS, and pure water as gas sources. The SiOF films are deposited by changing the FTES concentration in TEOS and FTES gas mixtures. The SiOF film deposition does not occur without the presence of FTES gas. The deposition rate increases with increasing the FTES concentration, then saturates at about 12 nm/min while the FTES concentration is 80%. The relationship between the film deposition rate and the FTES percentage in TEOS and FTES gas mixture is not linearly proportional. The deposited SiOF film properties such as refractive index, Si‒O bond nature, residual OH content, etching rate (1:30 buffered hydrofluoric acid), and leakage current are almost independent of the FTES concentration in the range from 20 to 100%. Residual fluorine concentrations for the SiOF films deposited at the FTES concentrations of 20, 50, 80, and 100% are 1.91 × 1021, 1.82 × 1021, 1.51 × 1021, and 1.51 × 1021 atom/cm3, respectively. The conformability of the SiOF films on Al wiring patterns is close to 100%. The formation mechanism of SiOF film is then described in a series of five chain reactions.