Density measurement of particles in rf silane plasmas by the multipass laser extinction method

Abstract

Measurement of the time evolution of the particle number density was investigated in rf silane plasmas by using the multipass laser extinction method. A He-Ne laser beam underwent multiple reflections on one horizontal plane of the plasma. The extinction signal increased in proportion to the beam pass numbers. A 10(11) cm(-3) density of 8 nm radius particles was measured at 10 s in a 32 mTorr and 50 W discharge using nine passes. The primary particle density was obtained by comparing the measured particle sizes with the calculated sizes from the light extinction signals and the Brownian free molecule coagulation model. (c) 2007 American Institute of Physics.