Surface reactivity measurements for OH radicals during deposition of SiO2 from tetraethoxysilane/O-2 plasmas

The surface reactivity of OH radicals has been measured during plasma deposition of SiO2 from tetraethoxysilane (TEOS)-based plasmas by the Imaging of Radicals Interacting with Surfaces (IRIS) method. This technique combines molecular beam and plasma technologies with spatially-resolved laser-induced fluorescence to provide two dimensional images of radical species during surface modification. OH radicals were not detected in a 100% TEOS plasma, but were observed in 20% TEOS/80% O-2 plasmas. The reactivity of OH is measured as 0.40 +/- 0.10 while depositing SiO2 on a 300 K Si substrate. This intermediate reactivity indicates that OH may play a role in formation of SiO2 films.