Al₂O₃ thin films prepared by plasma-enhanced chemical vapor deposition of dimethylaluminum isopropoxide

Al₂O₃ thin films were deposited by plasma-enhanced chemical vapor deposition using a dimethylaluminum isopropoxide precursor in the absence of additional oxygen sources. The deposition rate ranged from 0.77 to 1.07 Å/s and increased with increasing deposition temperature between 300 and 500 °C. The O/Al ratios in the films deposited at 300–500 °C were ~ 1.5, consistent with the formula Al₂O₃ and the carbon contents were 8.3–9.7 at.%. The film deposited at 30 °C had relatively higher values of O/Al ratio (2.04) and carbon content (47.1 at.%). Al2p, O1s, and C1s peaks observed from X-ray photoelectron spectroscopy analysis were mainly attributed to Al₂O₃. Fourier transform infrared analyses indicated that the functional groups such as Al₂O₃ bending and stretching vibrations were primarily from Al₂O₃ species with some carbon contents. From the dry etching test, the Al₂O₃ film deposited at 400 °C had the high etch selectivity of 9.13 over SiO₂, which showed the potential for application to the dry etch hard mask material. - Highlights: • Plasma-enhanced chemical vapor deposition of Al₂O₃ thin films • Dimethylaluminum isopropoxide used as precursor without additional oxygen sources • Films deposited at 300–500 °C were composed of Al₂O₃ and carbon content was 8.3–9.7 at.%. • Al₂O₃ film deposited at 400 °C has potential application as dry etch hard mask material.