Resonant CO2 laser-induced breakdown in polyatomic molecules

Summary The onset of CO₂ laser-induced breakdown has been observed by irradiating several polyatomic species (SiH₄, NH₃, hydrocarbons, fluorohydrocarbons) at a wavelength resonant with an IR active vibration. Primary fragmentation and subsequent ion and radical secondary reactions have been monitored detecting the spontaneous luminescence with a gateable optical multichannel analyser. The resonant laser-induced processes can be of importance in etching reactors where hydrocarbons and fluoro-hydrocarbons are commonly used, as well as in laser chemical vapour deposition reactors for the production of sinterable Si₃N₄ and SiC powders.