Effect of the Thickness on the Resistivity 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) 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 SHB-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 the 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 c-urrent in the event of rare spark discharges inside them caused by the registration of random highly ionizing pa-rticles.