| Abstract
| - The surface interactions of OH(X2Π) radicals during SiO2 deposition from 1,3,5,7-tetramethylcyclotetrasiloxane(TMCTS)/oxidant (O2 or N2O) and dimethyldimethoxysilane (DMDMOS)/oxidant (O2 or N2O) plasmas havebeen measured by using the imaging of radicals interacting with surfaces (IRIS) method. The reactivity ofOH at the surface of a growing SiO2 film has been determined as a function of the applied rf plasma power(P), the precursor-to-oxidant ratio, and the substrate temperature (Ts). For both Si precursors, the surfacereactivity (R) of OH during SiO2 deposition on a 300 K Si substrate is ∼0.60 and is unaffected by changingprecursor:oxidant ratio but does increase slightly with P. In contrast, at higher substrate temperatures (Ts>350 K), R decreases to 0.16 ± 0.10 for 1:10 TMCTS/O2 plasma (P = 100 W) and to 0.42 ± 0.03 for 1:10DMDMOS/O2 plasma (P = 100 W). The rotational (ϑR) and translational (ϑT) temperatures of the OHradicals have also been determined. The formation and role of OH in SiO2 deposition are discussed andcompared with previous results for TEOS/O2 plasmas.
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