Nano-Fabrication of Nano-Crystalline Diamond Films Grown by Microwave Plasma-Assisted Chemical Vapor Deposition

Abstract

In order to produce nano-scaled ultra-fine patterns into diamond films, a nano-crystalline diamond film with very flat surface has been synthesized. The fabrication process for a nano-scaled patterning in the nano-crystalline diamond film has also been developed. The nano-crystalline diamond film was grown on a silicon wafer by the microwave plasma-enhanced chemical vapor deposition with 1.0 % nitrogen addition in the gas phase. The grown diamond film consisted of nanometer-sized crystals has a smaller surface roughness of Rms=18 nm compared to nitrogen-undoped polycrystalline diamond films. The nano-crystalline diamond film was fabricated into ultra-fine patterns by the e-beam lithography and the reactiveion etching technique. In these processes, one of the key factors for the ultra-fine patterning was a selection of the mask material. The amorphous silicon nitride thin-film was revealed to be appropriate for the etching mask. As the nano-crystalline diamond film etching gas, a mixture of oxygen and a small amount of tetrafluorocarbon was effective for obtaining a higher aspect ratio pattern with little residue at the etched surfaces. We have succeeded in producing nano-scaled ultra-fine patterns into nano-crystalline diamond films with a minimum line-width of 100 nm.