Deposition of diamond-like carbon films using the screen grid method in electron cyclotron resonance chemical vapor deposition

Abstract

The deposition of diamond-like carbon (DLC) films from a mixture of hydrogen and methane using the electron cyclotron resonance chemical vapor deposition method is reported. A new technique based on a dc bias applied to a two-tier screen grid positioned above the substrate has been used to provide an electric field to accelerate the ions towards the substrate during deposition. The structural characteristics of the DLC films have been studied using Raman spectroscopy. Under conditions of 400 W microwave power and 6.5 mTorr process pressure, films deposited using the screen grid method were found to be hard and diamond-like and to contain a low bonded hydrogen content, as opposed to films deposited conventionally with dc bias applied directly to the substrate holder. The results showed that the dc bias applied to the lower grid of the screen grid fixture has the effect of accelerating the ionic species to impinge onto the substrate, hence promoting DLC film growth.