Diamond-Like Carbon Thin Films from Low-Pressure and High-Density CH₄ Plasma

Abstract

DLC thin films were grown using a low-pressure high-density CH4/Ar plasma on glass substrates in a planar RF (13.56 MHz) inductively coupled plasma (ICP) CVD system. Using a plasma triggered by RF power to a mixture of 20 sccm CH4 and 50 sccm Ar gas maintained at a low pressure of ∼30 mTorr, a series of samples were prepared by varying the substrate temperature and then changing the RF power. The optimised DLC films, obtained at 500 °C and 900 W demonstrated a high optical transmission of ∼97 % corresponding to awideoptical band gap of ∼3.58 eV; and a minimum of ID/IG ∼0.61 along witha maximum ofIDia/ID ∼1.32 in Raman analysis established the maximum sp3/sp2 content in the carbon network.