Dual-mode radio frequency/microwave plasma deposition of amorphous silicon oxide thin films

Abstract

A new dual-plasma (surface wave-coupled microwave and capacitively-coupled radio frequency) plasma enhanced chemical vapor deposition reactor for high growth rate deposition of amorphous insulating alloys has been developed. A high degree of flexibility for thin film material synthesis is expected, because the energy of the ion bombardment can be controlled independently of the microwave plasma chemistry. In situ spectroscopic ellipsometry is used for the optimization of the dual-mode plasma deposition of hydrogenated silicon oxides a-SiO x :H (with 0 ≦ x ≦ 2) providing monitoring of the index of refraction and deposition rate. A new procedure for the real-time calculation of both parameters is reproted. The growth rate of nearly stoichiometric oxides increases as a function of the oxygen flow rate with a maximum value of 33 Å s −1 using a 315 W microwave power.