Sulfur hexafluoride (SF6) as fluorine dopant precursor for production of fluorine doped tin oxide films by MOCVD

SF₆ was investigated as an alternative F source for preparing fluorine doped tin oxide films (SnO₂:F). SnO₂:F films were prepared on glass by low pressure MOCVD using tetramethyltin (Sn(CH₃)₄) and O₂ with SF₆ between 500°C and 650°C and 10-65 mol% SF₆. These were compared to un-doped SnO₂ and SnO₂:F grown with CBrF₃. SF₆ required higher thermal activation than CBrF₃. High electron mobility (~40 cm²/V-s) and low resistance (6.5×10^-3 ¿-cm) were achieved with SF₆ at ¿600°C. at 550°C and below, mobility was on the order of 4 cm²/V-s. Carrier concentrations were on the order of 10¹⁹ cm^-3, compared to 10²⁰ cm^-3 for CBrF₃ doped films. Optical transmission, reflectance and absorption spectra demonstrated transmittance of 80% in the visible spectrum. XRD showed SF₆ generated films of different crystal structure than CBrF₃. SIMS Showed a uniform F concentration of 1.5×10¹⁹ atom/cm³ from SF₆, but SF₆ did not incorporate as much F into the films as CBrF₃ (7.5×10²⁰ atoms/cm³). Sulfur contamination was not found.