The electrical properties of alumina films formed at substrate temperatures as low as 27 degrees C using tri-methyl aluminum (TMA) and molecular OF oxygen (O-2) by catalytic chemical vapor deposition (Cat-CVD) have been investigated by capacitance-voltage (C-F), current-voltage (I-V) measurements and X-ray photoelectron spectroscopy (XPS). Substrate temperature dependence of dielectric constant 2 and leakage current of the films has been explained on the basis of deficiency in oxygen. Interface trapping density of the order of 10(9) ev(-1) cm(-2) has been obtained. Angle resolved XPS measurements have revealed that the direct bonding of alumina and Si was realized with very small interface trapping density. (c) 2007 Elsevier B.V. All rights reserved.