Effect of catalyst layer density and growth temperature in rapid atomic layer deposition of silica using tris(tert-pentoxy)silanol.

Rapid atomic layer deposition (RALD) of SiO₂ thin films was achieved using trimethyl-aluminum and tris(tert-pentoxy)silanol (TPS) as the catalyst and Si precursor, respectively. A maximum growth rate as high as ∼28 nm/cycle was obtained by optimizing the catalyst layer density, whereas the previous reports showed lower values of 12 to 17 nm/cycle [Hausmann et al. Science2002, 298, 402-406; Burton et al. Chem. Mater. 2008, 20, 7031-7043]. When the growth temperature was increased from 140 to 230 °C, the growth rate was not much reduced and the TPS pulse time showing a saturated growth rate became rather longer. Si-CH₃, Si-OH, and Si-H bonds were not detected in infrared spectra from the RALD SiO₂ film grown at 230 °C. The film quality could be enhanced substantially by applying a higher growth temperature and an in situ post plasma treatment process.