You have to be more precise with your question - advantage compared to what?

advantages compared to microwave frequency and arc plasma

A Bharatish Rao : this clarification helps indeed. Compared to MW plasma, an rf source is easier to handle because in the case of a microwave you need either a horn antenna or a very fine-tuned process chamber that acts as a resonator and creates a standing MW inside. This is tricky.

Compared to an arc plasma you have less temperature on the substrate surface (usually) and less abrasion. If you have a free burning arc you can get several thousand K temperature on the substrate, which can destroy it or prevent a decent DLC film from forming. Both of these issues are easily prevented with an rf plasma (also the substrate temperature can be easier regulated in the rf case). Furthermore, arcs are usually burning on relatively small areas of the substrate while an rf plasma can be applied to larger surface areas (depending on the working gas pressure).

Thank you very much