XPS and ellipsometric study of DLC/silicon interface

Diamond-like carbon (DLC) films were prepared by plasma-enhanced chemical vapour deposition from the mixture of methane and argon on silicon substrates. Films were characterised by multi-sample modification of variable angle spectroscopic ellipsometry, Ellipsometry showed that there is a transition interlayer between the DLC film and the silicon substrate that cannot be attributed to a thin silicon dioxide layer but rather to amorphous silicon and/or a modified oxide layer. TRIM calculations revealed that argon or carbon ions could not produce a significant layer of amorphous silicon because the depth of target atom displacements is below the thickness of a native oxide layer. The chemical composition of a DLC film profile including a DLC/silicon interface was studied by X-ray photoelectron spectroscopy (XPS) coupled with argon sputtering of the 34 nm thick DLC film. The DLC/silicon interface composed of less than 6% of oxygen and a gradually decreasing and increasing carbon and silicon percentage, respectively (C) 2001 Elsevier Science Ltd. All rights reserved.