In situ, real-time observation of Al chemical-vapor deposition on SiO2 in an environmental transmission electron microscope

Abstract

A technique for in situ observation of chemical-vapor deposition (CVD) is demonstrated. An environmental transmission electron microscope with 3.8 Å resolution was used for real-time, in situ observation of Al CVD onto SiO2 from trimethylamine alane (TMAA). Nominal TMAA pressures from 50 to 400 mTorr and substrate temperatures from 50 to 200 °C were investigated for deposition onto both TiCl4 pretreated and untreated surfaces. For deposition onto untreated surfaces, low nucleation densities and polycrystalline, dendritelike growth were observed for all deposition temperatures with deposition commencing at about 150 °C. Deposition on TiCl4-treated surfaces resulted in polycrystalline films with grain sizes of a few nm and lower-temperature (100 °C) growth.