Fracture toughness, hardness and elastic modulus of hydrogenated amorphous carbon thin films produced from butene gas deposited by chemical vapor deposition on silicon were measured by depth sensing indentation. Voltage bias varying from -60 to -400 V and pressures of 2 and 8 Pa were used for deposition. Cube corner indentation produces film chipping at loads lower than 400 mN. A new approach to measure toughness was proposed to determine the energy released during film chipping. Fracture toughness results from this new approach are in between of the ones obtained from methods proposed in the literature. (c) 2005 Elsevier B.V. All rights reserved.