The effect of He or Ar/O-2 plasma treatment on Si surface prior to chemical vapor deposition of SiO2

Abstract

The effect of O-2 plasma pretreatment on the SiO2/Si interface property was studied using direct plasma varying the plasma power, He or Ar/O-2 ratio and the pretreatment time. The decrease of the pretreatment plasma power decreased the plasma damage and improved the interface property. The addition of He in O-2 glow discharge improved the electrical and the interface properties and there was an optimum He/O-2 ration. The improvement of the interface property by the Ar/O-2-plasma pretreatment was better than that by He/O-2, which is believed to be due to the lower oxidation rate of the Si surface. C-V analysis showed that the P-b center defect density was influenced by plasma pretreatment process parameters. To investigate the oxidation states near to and at the SiO2/Si interface, X-ray photoelectron spectroscopy depth analysis was used and the gas phase in the glow discharge was investigated using optical emission spectroscopy analysis at various experimental conditions. (C) 2004 Kluwer Academic Publishers.