A multilayer a-C:N film electrode deposition process has been developed using the filtered cathodic vacuum arc (FCVA) system based on the highly conductive silicon wafer with a Ti interlayer for ohmic contacts. Its robustness has been evaluated under the practical electrochemical conditions and shows that it has no pin-hole and no breaking point happened when voltages are applied on it. Extremely large errors will arise in the electrochemical characterizing a-C:N film electrodes (hydrogen and oxygen evolutions and oxygen reduction) when there is a pin-hole or a broken point in the films. And the error caused by the non-ohmic contact amplifies at a high potential range. It is expected that non-robust a-C:N film electrodes and non-ohmic contacts mislead the electrochemical characterizing on a-C:N films. (C) 2007 Elsevier B.V. All rights reserved.