In-situ PECVD-based stoichiometric SiO2 layer for semiconductor devices

Abstract

We propose an in-situ stoichiometric SiO2 layer deposition using plasma-enhanced chemical vapor deposition (PECVD) to replace typical outside SiO2 deposition for semiconductor devices, such as thermal oxidation and/or wet chemical oxidation. The SiO2 films deposited in a silane (SiH4), argon (Ar), and carbon dioxide (CO2) precursor gas mixture are compared to those deposited in a standard SiH4+CO2 plasma environment. Ar gases are introduced into the plasma environment of silane (SiH4) and carbon dioxide (CO2) to improve the optoelectronic properties and stoichiometry of SiO2. The addition of the Ar gases promotes the dissociation of SiH4 and CO2, resulting in an increase in the deposition rate and a decrease in the SiO2 refractive index. The addition reduces the dielectric constant of SiO2 by analyzing the metal-oxide-semiconductor structure. The resultant SiO2 shows excellent surface passivation of crystalline silicon wafers. The mechanism of SiO2 formation in PECVD with mixture gases is thoroughly addressed. The in-situ PECVD-based stoichiometric SiO2 layer is expected to reduce the complexity of the semiconductor device procedure. © 2023 Elsevier B.V.