A crystalline hydrogenated carbon film obtained by plasma enhanced chemical vapor deposition

A hydrogenated carbon film in a crystalline form has been prepared on Si (0 01) using a radio frequency plasma enhanced chemical vapor deposition proce ss. The crystalline film is metastable and has polymer-like features with a mass density of about 1.20 g/cm(3) and an optical band gap of about 2.75 e V. The stability of the structure and properties of the film was studied by thermal annealing at successively higher temperatures in the air. Upon hea ting, the film showed a two-step structure change which resulted in a two-s tep change in the film properties. The relationship between the properties and the bonded hydrogen in the film was also discussed. (C) 1999 American I nstitute of Physics. [S0021-8979(99)05715-1].