BEHAVIOR OF SI ATOMS IN A SILANE ELECTRON-CYCLOTRON-RESONANCE PLASMA AT HIGH DISSOCIATIONS

The Si atom density at the 3p(2) P-3(2) level in electron cyclotron re sonance SiH4/H-2 and SiH4/Ar plasmas was measured as a function of tot al pressure from 0.6 to 3.3 Pa at a microwave power of 400 W and a SiH 4 flow rate of 6 seem using ultraviolet absorption spectroscopy. Paren t SiH4 molecules in SiH4/H-2 and SiH4/Ar plasmas were found to be cons iderably dissociated using infrared diode laser absorption spectroscop y. The Si atom density in the SiH4/H-2 plasma was larger than that in the SiH4/Ar plasma, which was quite different from that in the capacit ively coupled rf SiH4 plasmas. Behaviors of the Si atom density are di scussed on the basis of the rate equation for Si atoms. It was conclud ed from a comparison of the behavior of the density and generation rat e of Si atoms that the diffusion loss was comparable to the reaction l oss in the removal process of Si atoms in the case of H-2 dilution, wh ile the reaction loss was dominant in the case of Ar dilution. (C) 199 6 American Vacuum Society.