DLC films are deposited by using a modified FCVA system. Carbon amorphous network, surface roughness, internal compressive stress, resistivity, and Hall mobility are studied as a function of nitrogen flow rate (0—10 seem). As the nitrogen content is increased in the carbon network, the size of sp2 clusters is increased, the internal compressive stress is decreased, and the resistivity is remarkably decreased. The RMS values of the surface roughness are measured to be in the range of 0. 2~~0.5nm. The Hall mobility of DLC film with 3 seem of nitrogen added is 3.22 cm2/V • s.