Experimental characterization of the deposition of silicon suboxide films in a radiofrequency magnetron reactive sputtering system

Sputter deposition of silicon suboxide films in a radiofrequency (rf) magnetron discharge using oxygen gas as a reactive species has been studied by a combination of plasma and film characterization techniques. The deposited films are silicon suboxides (SiOx, 0≤x≤2). Using an energy-resolved mass spectrometer we found an impingement rate of SiO+ ions on the deposition surface, which is comparable in magnitude to that of Si+, so a significant contribution of SiO to the Si and O incorporation in the suboxides cannot be ruled out. Increase of the oxygen flow beyond the point of SiO2 deposition is characterized by a strong decrease of the Si+ ion arrival rate on the growth surface. At the same time, the SiO2+ arrival rate is increased, indicative for the increased oxidized state of the cathode. Number of atoms of the various kinds in the deposited layers have been determined by using Rutherford backscattering (RBS) and Elastic recoil detection (ERD) and correlated with the results of the plasma characterization.