Preparation of boron nitride thin films by microwave PECVD and their analytical characterisation

Hexagonal boron nitride films on Si(100) substrates are formed from the sys tem N-2/B(OCH3)(3) (TMOB) by microwave plasma enhanced chemical vapour depo sition (PECVD). The parameters substrate temperature, deposition time and c omposition of the process gas mixture were varied. The stability of the dep osited layers mainly depends on the substrate temperature during the deposi tion process. Layers formed below 650 degreesC showed strong decomposition features by contact with air humidity. Above this temperature very stable l ayers could be produced. This was confirmed by hydrolysis tests. The struct ural growth of the boron nitride layers was investigated by means of transm ission electron microscopy (TEM) and electron energy loss spectroscopy (EEL S). Three different growth zones were observed within the layers. The compo sition was determined by electron probe microanalysis (EPMA) and elastic re coil detection analysis (ERDA). Infrared and Raman spectroscopy were used f or qualitative investigation of the BN layers.