Amorphous aluminum silicate films by metal-organic chemical vapor deposition using aluminum-tri-sec-butoxide and tetraethyl orthosilicate

Amorphous aluminum silicate films with film thickness of 0.5–2.7 μm were prepared on glass and silicon substrates by metal-organic chemical vapor deposition using a mixture of tetraethyl orthosilicate (TEOS), aluminum tri-sec-butoxide (ATSB), and argon. These films were studied by choosing different substrate temperatures and reactant inputs. The apparent activation energy of the aluminum silicate films is related to surface reaction between reactive ATSB and less reactive TEOS. Microstructure was examined by scanning electron microscopy and atomic force microscopy. The Al content in films increased with increasing the ATSB content and with decreasing deposition temperature, while the Si content increased with the increase in the TEOS content. The dependence of film composition on deposition temperature can be related to the values of activation energy of the two systems. Mechanical properties, such as internal stress, hardness, and adhesion, of the aluminum silicate films were evaluated. Optical properties, such as refractive index and optical transmittance, were also measured.