Aluminum oxide has been highlighted as a promising surface passivation layer for p-type silicon surface. To-date, most of the studies have focused on aluminum oxide layers deposited with atomic layer deposition systems which have lower throughput than industrial plasma-based systems. In this study, the effects of deposition conditions on the electrical and optical properties of aluminum oxide deposited by an industrial plasma enhanced chemical vapor deposition system are presented. Low saturation current density of 1.9 fA/cm 2 was achieved by as deposited layer on p-type Czochralski wafer. The most significant deposition process factor for high quality surface passivation was found to be the gas flow rate ratio between nitrous oxide and tri-methyl-aluminum.