The mechanism of alumina fort-nation from tri-methyl aluminum (TMA) and oxygen (02) using catalytic-chemical vapor deposition (Cat-CVD) with an iridium catalyzer was investigated by quadrupole mass spectrometry (QMS). Above 600 degrees C, TMA decomposed into Al and CH3. Aluminum in the presence of O-2 caused a decrease in O-2 and the creation of alurnina on Si crystals. These results imply that O-2 and Al produced AlO as expected. The iridium catalyzer was resistant to oxidation. MIS diodes with 17-nm-thick alumina gates were produced with a hysteresis shift voltage of 0.01 mV and a fixed charge density of 6.7 x 10(11) cm(-2). (c) 2005 Elsevier B.V. All rights reserved.