Effects of O-2- and N2O-plasma treatments on properties of plasma-enhanced-chemical-vapor-deposition tetraethylorthosilicate oxide

The high quality silicon oxide films were prepared by plasma-enhanced chemi cal vapor deposition (PECVD) using tetraethylorthosilicate (TEOS)-oxygen ba sed chemistry. The O-2- or N2O-plasma treatments were performed on the as-d eposited films as an attempt to improve the properties of the TEOS oxide fi lms. TEOS oxide film deposited at lower pressure had lower Si-OH content, l ess carbon impurity, and flatter surface, and hence had better electrical p roperties. Both O-2- and N2O-plasma would decrease the oxygen content of th e oxide film, which led the composition of the film to deviate from the sto ichiometric SiO2. The O-2-plasma treatment did not show the encouraging eff ect on the chemical structure and electrical properties of the TEOS oxide f ilms. In contrast, the N2O-plasma treatment could be a promising means to i mprove the breakdown field and leakage current density of the TEOS oxide fi lms, which was accomplished by the N2O-plasma effect to facilitate the pass ivation of dangling bonds, linking reaction of Si-OH bonds, nitridation rea ction and densification of the amorphous silicon oxide network.