Amorphous carbon films (ACFs) have recently emerged as one of the best candidates for etching-resistant hardmask materials in advanced semiconductor manufacturing processes. Etching resistivity of ACFs is known to be improved by controlling the relative abundance between sp(2) and sp(3) bonds. We have investigated the relative abundance between sp(2) and sp(3) bonds in several ACFs, fabricated by plasma-enhanced chemical vapor deposition at different temperatures, which were analyzed by using X-ray photoemission spectroscopy, Raman spectroscopy, and transmission electron microscopy. We found that the relative abundance of sp(2) bond increased as the growth temperature was raised. Furthermore, the ACFs eventually evolved into nano-crystalline graphite with increasing growth temperature.