Cracking of Selected Hydrocarbon Gases in Low-Power, Low-Pressure rf Plasma

摘要

The cracking of four hydrocarbons, C_3H_8, C_2H_6, 4and CH_4, respectively, in an Arplasma has been investigated. Ions observed in electron impact ionization mass spectra of theplasma are used to probe the neutral components of the plasma. A matrix of data of ionintensities under varying rf powers (O-30W) and gas pressures (100-400 mTorr), for the fourhydrocarbon gases, respectively, has been collected, and the rates of the depletion of thehydrocarbons in the plasma and the formation of H_2from the cracking of hydrocarbons,under the varying experimental conditions, have been evaluated. Among the four hydrocarbons,C_2H_4undergoes cracking most readily and CH_4yields the amount ofH_2by cracking.