DEPOSITION OF DIAMOND-LIKE CARBON-FILMS BY PLASMA-ENHANCED CHEMICAL-VAPOR-DEPOSITION

Diamondlike carbon (DLC) films have been deposited by various techniqu es including remote plasma enhanced chemical vapor deposition (RPECVD) , cyclic and noncyclic deposition by PECVD. Ar gas was exploited as th e plasma gas, while CH4/H-2/He mixture was for the deposition of the D LC film. CF4 and He were introduced for etching the deposited DLC film . With increasing hydrogen content, the optical bandgap increases and the hardness of the film decreases. The optical bandgap of the DLC fil ms grown by RPECVD, noncyclic and cyclic PECVD techniques are 2-3.8, 1 .2 and 1.2-1.4 eV, respectively. We find out that the films deposited either by RPECVD or noncyclic PECVD techniques contain hydrogen in a s ignificant amount, while the film deposited by cyclic PECVD film conta ins no hydrogen. Assuming that graphite phase (sp(2)) and diamondlike phase (sp(3)) are simultaneously deposited during growth, the graphiti c phase related to hydrogen seems then to be etched away during the et ching cycle by CF4. (C) 1997 Published by Elsevier Science S.A.