HYDROGEN-FREE DIAMOND-LIKE CARBON DEPOSITED BY A LAYER-BY-LAYER TECHNIQUE USING PECVD

Abstract

We developed a hydrogen-free diamond like carbon (DLC) film by a novel deposition technique of a layer-by-layer technique using plasma enhanced chemical vapor deposition (PECVD) in which a repeated deposition of a thin DLC layer and subsequently CF 4 plasma treatment on its surface have been carried out. The electrical, optical and structural properties of the DLC films deposited depend on the CF 4 plasma exposure time. The hydrogen content is less than 1 at % when the CF4 plasma exposure time is 140s. Its emission current is much higher and stability is much improved compared with conventional DLC.N-type, hydrogen-free DLC could be obtained by N ion doping N2 gas-phase doping in the CF 4 plasma. The optimum [ N 2][ CH 4] flow rate was found to be 9% for the efficient electron emission, at which the onset-field was 7.2 V /μ. The nitrogen gas-phase doped hydrogen-free DLC coating on Mo tip field emitter arrays (FEAs) increased the electron emission current from 160μ A to 1.52 mA and improved the stability in electron emission current.