Evaluation of Argon as a Carrier Gas of Liquid Material Vaporization During the Plasma-Enhanced Chemical Vapor Deposition (PECVD) Silicon Oxide Process

Abstract

This paper investigated the potential use of argon (Ar) as an alternative carrier gas to helium (He) during the tetraethyl orthosilicate–silicon dioxide (TEOS–SiO2) process using a plasma-enhanced chemical vapor deposition (PECVD) system. Due to the shortage or depletion of conventional He gas, it is important to find alternative gases. This study investigated the effects of the Ar carrier gas on the vaporization efficiency and properties of SiO2 film in the PECVD TEOS–SiO2 process for different process conditions, such as flow rate and plasma power. Ar showed a much higher vaporization efficiency and faster deposition rate than He due to its higher molecular weight and plasma density, indicating that SiO2 film can be deposited considerably faster with less Ar gas. While changes in the film density and residual film stress were also noted depending on the types of carrier gas and amounts or types of plasma power, these changes were insignificant and within the controllable process range during the PECVD process. Therefore, the use of Ar gas can reduce costs and contribute to improvements in productivity without affecting the quality of SiO2 film.