Assessment of reference reaction models relevant for the oxidation of SiH4 with O2 against a comprehensive validation database

Abstract

Although silane is one of the most widely used source of silicon for material synthesis, its chemical kinetics is still not completely understood. This study assesses the performances of three reference reaction models (Mével, PeOx, and Babushok) for Si-containing mixtures using a large range of experimental conditions (T = 801-1768 K and P = 91-138 kPa) relevant for the oxidation of SiH4 by O2. These three reference reaction models were previously used for a study on pyrolysis of SiH4 and Si2H6. The validation is performed subsequently on H2-O2 and SiH4-O2-diluent mixtures with and without H2 addition. The validation set is composed of more than 200 conditions including SiH4, SiH2, and OH* species profiles and characteristic reaction times based on pressure and OH* signals. This study evidences that (i) the three models satisfactory reproduce the data for H2-O2 mixtures; (ii) for SiH4-H2-O2 mixtures, Babushok's model overestimates SiH4 reactivity; (iii) while Mével and PeOx satisfactory reproduce the species profiles in most of the conditions, Mével has a lower mean absolute error (MAE), equals to 140 µs, on all temperature-resolved profiles compared to PeOx (192 µs) and Babushok (243 µs). As most of the present database rely on OH* profiles, more experimental data are required to assess the mechanisms and to better understand the SiH4 oxidation kinetics.