Observation of Si cluster formation in SiO2 films through annealing process using x-ray photoelectron spectroscopy and infrared techniques

SiO2 films having high breakdown characteristics were deposited by a sputtering-type electron cyclotron resonance microwave plasma at room temperature. As-deposited films were annealed in an Ar ambient at temperatures ranging from 450 to 1000 degrees C. Transmitted infrared (TR) absorption and x-ray photoelectron spectroscopy (XPS) were used to characterize the as-deposited and annealed films. XPS measurements indicated that the as-deposited films had an approximately stoichiometric composition containing a few intermediate SiOx(x not equal 2) species and Ar atoms around some dangling-bond defects. The dependence of XPS spectra on annealing temperature showed that steep diffusion of the Ar atoms occurs at annealing temperatures of 450-550 degrees C and the SiOx species separate into SiO2 phase and Si clusters by an annealing process of 750-950 degrees C. Based on the full width at half-maximum variations of Si 2p XPS spectra and Si-O stretching mode of IR spectra for the annealed films, we discuss the Si cluster formation in SiO2 films through the annealing process. (C) 1998 American Institute of Physics.