Al2O3 growth optimisation using aluminium dimethylisopropoxide as precursor as a function of reaction conditions and reacting gases

Aluminum oxide films were grown in a hot-wall low-pressure metal organic ch emical vapor deposition (MOCVD) system using aluminum dimethylisopropoxide as precursor. Experimental reaction conditions and the reacting gas (O-2, H 2O, N2O) have been systematically varied with the aim to decrease the depos ition temperature and obtain transparent, dense and carbon-free films. Chan ges in the gas phase composition were studied by FT-IR spectroscopy using a n in-line cell. The reactor temperature ranged from 230 degreesC to 380 deg reesC. The microstructure of the films was investigated by X-ray Diffractio n, while the surface chemical composition was studied by X-ray Photoelectro n. Atomic Force Microscopy was employed to analyze the surface morphology o f the films as a function of reaction conditions and reacting gases. The be st performances have been obtained using dry oxygen at 1000 Pa and oxygen m ixed with water vapor at 100 Pa. High growth rates such as 140 nm min(-1) h ave been obtained at 270 degreesC in the latter case. Different reaction me chanisms have been proposed in the two cases.