Effect of the thickness on electrical resistance of thin diamond-like carbon coatings on silicon substrate

Abstract

The relationship between sp2/sp3-hybridizations ratio of atomic bonds in diamond-like carbon ( DLC --- Diamond-Like Carbon) and its electrical resistivity for coatings with a thickness in the range 22-70 nm prepared by vacuum arc deposition on silicon substrate of the KDB-8 brand has been established. It is established, that an increase in the coating thickness from 22 to 70 nm is accompanied by a decrease in the specific transverse electrical resistance of samples from 17 to 2 GΩ·m. This effect is explained by an increase in the proportion of carbon atoms with sp2-hybridization of electronic orbitals from 86 to 91%, which leads to the appearance of an additional number of π-bonds. A mathematical model, describing the spatial distribution of current when measuring transverse I-V characteristic, has been developed. The results obtained will be useful in creating resistive layers on the electrodes of gas-discharge detectors of charged particle to limit the amount of current in the event of rare spark discharges inside them caused by the registration of random highly ionizing particles. Keywords: ( DLC), electrical properties of thin films, hybridization of electronic orbitals, Raman scattering, I-V characteristic.