Multiple photon excited SF₆ interaction with silicon surfaces

Abstract

Infrared laser induced SF6-silicon interactions have been studied and the surface reaction yields have been determined as a function of the laser frequency, the laser intensity, and the gas pressure in both perpendicular and parallel beam incidences on the solid surfaces. The results clearly show that vibrationally excited SF6 molecules promoted by CO2 laser pulses are very reactive to silicon, particularly when the solid is simultaneously exposed to the intense ir radiation. The laser excitation of the Si substrate alone cannot cause the heterogeneous reaction to occur. The present gas-solid system thus provides an example which clearly establishes the direct correlation between surface reactivity and vibrational activation. Additional experimental measurements also demonstrate that the thermal fluorine atoms generated by SF6 multiple photon dissociation at high laser intensities can react with silicon to form volatile product. The study thus provides further insight into the silicon-fluorine reaction dynamics. © 1981 American Institute of Physics.