IR and Raman absorption spectroscopic studies of APCVD, LPCVD and PECVD thin SiN films

Silicon nitride films prepared by different chemical vapour deposition (CVD) techniques are studied by infrared (IR) and Raman spectroscopy. The main peak in the IR spectrum for films obtained in atmospheric pressure CVD (APCVD) and low pressure CVD (LPCVD) reactors is at 830 and at 811 cm(-1), respectively, while for plasma-enhanced CVD (PECVD) films it is at 826 cm(-1). For layers deposited by PECVD small peaks are observed at about 3300 cm(-1) and in the region 3200-3500 cm(-1) which indicates the presence of N-H and O-H bonds. Scanning electron microscopy (SEM) shows that the surface of the LPCVD samples is smoother than the surfaces of the APCVD and PECVD samples. A correlation between the layer characteristics such as the refractive index (n), the dielectric constant (a), the etching rate (v(etch)), the IR spectrum, etc. and the type of the deposition system is established. (C) 2002 Elsevier Science Ltd. All rights reserved.