Formation of intermediate SiCN interlayer during deposition of CN x on a-Si:H or a-SiC:H thin films B. Mitu a , G. Dinescu a,* , E. Budianu b , A. Ferrari c , M. Balucani c , G. Lamedica c , A. Dauscher d , M. Dinescu a a National Institute for Laser, Plasma and Radiation Physics, P.O. Box MG-36 Magurele, Bucharest 76900, Romania b Institute for Microtechnologies, Bucharest, Romania c INFM, Unit E6, University ‘‘La Sapienza’’, Rome, Italy d Ecole des Mines de Nancy, Laboratoire de Physique des Materiaux, Nancy, France Abstract Thin films of carbon nitride have been realized in a downstream RF plasma beam discharge generated in argon/nitrogen with carbon electrodes. The deposition has been performed on the top of a-Si:H or a-SiC:H layers previously deposited in diode type CVD reactor from methane and silane. The surface topography produced by the deposition procedures has been studied by atomic force microscopy (AFM) technique. The obtained samples have been investigated by secondary ions mass spectrometry (SIMS), Fourier transform infrared spectroscopy (FTIR) and UV–Vis optical absorption. It is shown that the formation of SiC and SiCN interlayers occurs, which is promoted by the reactions of plasma C, N, and CN gaseous species with the silicon atoms from the base film. # 2001 Published by Elsevier Science B.V. Keywords: Carbon nitride; Interlayer; Silicon carbonitride; Remote plasma 1. Introduction Silicon carbides and carbon nitrides are between the most interesting wide band gap materials with possi- ble applications in electronics and optics. Although there are difficulties in obtaining them in crystalline forms, the amorphous counterparts can also find applications. In previous works [1] it was shown, based on Fourier transform infrared spectroscopy (FTIR) and in-depth XPS measurements, that during deposition of carbon nitride thin films on top of amorphous hydrogenated silicon or silicon carbide layers, chemical bonds of Si–C and Si–C–N may appear at the separating interface. These chemical bonds are effective in the mechanical stability of such double structures and it is possible to affect the electrical and optical properties. Therefore, an exten- sive study of the nature and properties of the region were the frontier between the films build up is neces- sary. In this paper, new results based on atomic force microscopy (AFM), optical UV–Vis and secondary ions mass spectrometry (SIMS) investigations are presented and discussed in relation with previously performed FTIR and XPS measurements. 2. Experimental The a-Si:H and a-SiC:H layers have been prepared in a diode type reactor by RF (13.56 MHz) plasma Applied Surface Science 184 (2001) 96–100 * Corresponding author. Tel.: þ40-1-423-1226; fax: þ40-1-423-1791. E-mail address: dinescug@alphal.infim.ro (G. Dinescu). 0169-4332/01/$ – see front matter # 2001 Published by Elsevier Science B.V. PII:S0169-4332(01)00666-3