Investigation of the uniformity and coverage of CxNy : H overcoatings during PECVD in an inductively coupled plasma

The films were grown using an inductively coupled plasma with two different precursor gas mixtures: CH4/N-2 and C10H16/N-2 The lateral compositional u niformity of the specimens and the resultant substrate coverage are investi gated here using XPS, AES, Raman spectroscopy and SEM, X-ray photoelectron spectroscopy, because of the size of the x-ray beam use d (similar to 5 mm), gives a gross measure of the atomic concentration of t he surface. In turn, Auger analysis, using a 1 mu m spot E-beam, allowed th e compositional uniformity to be checked at a substantially higher lateral resolution. Additionally, Raman spectra collected from different regions of the surface confirm the outcome of the XPS and AES results obtained. In ad dition to XPS, AES and Raman spectroscopy, some SEM data were generated to illustrate the compositional and structural uniformity of the coating acros s the substrate surface. Such SEM images apart, no contribution of the subs trates used to the XPS or AES spectra obtained confirmed that the films exa mined (150-3000 Angstrom thick) were pinhole free. These investigations clearly show that the uniformity and the substrate cov erage are a function of the deposition regime, i.e. power level, base press ure, etc., and are strongly affected by the abundance of oxygen found in th e films. Copyright (C) 2000 John Wiley & Sons, Ltd.