Capacitance-voltage (C-V) characteristics of the as-grown metal (M)-carbon-oxide(SiO2)-semiconductor(Si) structures are examined at the frequency of I MHz and compared with the C-V characteristics of the conventional metal(Al)-SiO2-Si (MOS) Structures. The density of the oxide charge Q(o)/q is extracted from the experimental results. Q(o)/q was found to be I x 10(12) cm(-2) for the MOS structures and 7 X 10(11) cm(-2) for the metal-carbon-oxide-silicon structures. This difference can be attributed to the presence of the carbon layer which acts as a protective coating during metallisation of the wafers. (C) 2003 Elsevier Science Ltd. All rights reserved.349877880