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

Abstract Al 2 O 3 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 A/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 Al 2 O 3 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 Al 2 O 3 . Fourier transform infrared analyses indicated that the functional groups such as Al 2 O 3 bending and stretching vibrations were primarily from Al 2 O 3 species with some carbon contents. From the dry etching test, the Al 2 O 3 film deposited at 400 °C had the high etch selectivity of 9.13 over SiO 2 , which showed the potential for application to the dry etch hard mask material.