Simple Direct Monitoring of SiH3Radical and Particulates in a Silane Plasma with Ultraviolet Transmission Spectroscopy

The silyl radical ( SiH3) in a H2/SiH4rf plasma is successfully detected by an easy and inexpensive method, i.e., high-sensitivity ultraviolet transmission spectroscopy (UVTS). The diffusive absorption band of the SiH3radical is observed in the 205-240 nm region. The relative SiH3density is measured as a function of RF power from 20 to 100 mW/ cm2by UVTS. The UV transmittance is very sensitive to particulates in the plasma, thus enabling both particulates and SiH3radicals to be monitored simultaneously.