Time-resolved cavity ringdown spectroscopy as a monitoring technique of nanoparticles in pulsed VHF plasmas

Takehiko Nagai, A.H.M. Smets, M. Kondo

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review


Time-resolved cavity ringdown (t-CRD) spectroscopy has been applied to monitor the silyl (SiH3) radicals and nanoparticles in pulsed very high frequency (VHF) silane (SiH4)/hydrogen (H2) plasmas under microcryst. silicon (micro c-Si:H) deposition conditions. After the plasma ignition, a small const. cavity loss (.apprx.100 ppm) on time scales smaller than .apprx.1 s has been obsd., whereas on time scales larger than .apprx.1 s after plasma ignition, an addnl. cavity loss is obsd. By variation of the wavelength of the CRD laser pulse, we demonstrate that the cavity loss on time scales smaller than .apprx.1 s reflects the SiH3 absorption. On time scales larger than .apprx.1 s, the addnl. cavity loss corresponds to the loss of light due to mainly scattering at the nanoparticles. Under the conditions studied, the light scattering at nanoparticles can be described by Rayleigh scattering during its initial growth. After .apprx.2.5 s, the cavity loss reflects the transition of the scattering mechanism from dominant Rayleigh to dominant Mie scattering. These results are discussed in terms of nanoparticles growing in time and further confirmed by addnl. SEM analyses on the nanoparticles created in the plasma pulse. [on SciFinder (R)]
Original languageEnglish
Title of host publicationAmorphous and Polycrystalline Thin-Film Silicon Science and Technology--2007
PublisherMaterials Research Society
Publication statusPublished - 2007

Publication series

NameMaterials Research Society Symposium Proceedings
ISSN (Print)0272-9172


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