Synthesis and characterization of SiO2 films deposited using tetraethylorthosilicate/ozone at low processing pressures (10−1 to 10−3)

Abstract

High quality, low growth temperature SiO2 thin films are necessary for the fabrication of submicron devices. A new deposition technique for SiO2 films utilizing chemical vapor deposition (CVD) of tetraethylorthosilicate (TEOS) in an ultrahigh vacuum chamber at low processing pressures (10−1 to 10−3 Torr) has been investigated. Ozone is introduced to provide a source of active oxygen. The oxide was characterized by ellipsometry, infrared absorption spectrometry, and etch rate. Films for comparison were grown using TEOS/oxygen and TEOS only. Results indicate that the active oxygen substantially reduces the deposition temperature. It was also found that the growth rate is strongly affected by the processing pressure at these very low pressures. The effect of important parameters (substrate temperature, TEOS/ozone ratio, oxidizing agent, and processing pressure) on the resultant oxide growth rate and properties are addressed. Our findings are compared to results reported in the literature for plasma-enhanced CVD (PECVD) of SiO2 films grown in a similar pressure range and atmospheric CVD of SiO2 using an ozone ambient.