Molecular layer deposition of amine-containing alucone thin films

The deposition of organic thin films with accurate thickness and tailored functionality is an important step towards the development of gas sensors with high selectivity. In fact, thin films able to selectively interact with gas-phase analytes are central building blocks for the new generation of extremely sensitive sensors. In this contribution, we report on the molecular layer deposition of alucone thin films enclosing tertiary amine functions in their bulk. The sequential exposure of substrates to the metal precursor, trimethylaluminum, and to the organic linker triethanolamine was investigated for the growth of alucone thin films that contain tertiary amine groups. The systematic monitoring of the growth process was performed gravimetrically using a quartz crystal microbalance and by the analysis of the exhaust gas with mass spectrometry. The obtained films were analyzed by SIMS, XPS, FTIR and ellipsometry to perform elemental, chemical and optical characterization. A saturated deposition process was demonstrated and used for the growth of thin films that include nitrogen in their bulk. The obtained films exhibit a density of 2.35 g/cm3 and they dissolve readily in ultrasonic bath of acetone, but not in water.