ELECTRON-MICROSCOPY CHARACTERIZATION OF TIN FILMS ON SI, GROWN BY DC-REACTIVE MAGNETRON SPUTTERING

The structural characteristics of titanium nitride films deposited by d.c. reactive magnetron sputtering on (001) silicon wafers were studie d by cross-section transmission electron microscopy and in-situ spectr oscopic ellipsometry (SE). The growth habit of the films, the shape an d the size of the crystallites were investigated versus deposition tem perature, bias voltage and nitrogen flow rate. The surface micro-rough ness was also studied by atomic force microscopy. The films exhibit a columnar growth showing preferred orientation along (111) direction. H igh-resolution transmission electron microscopy (TEM) observations rev eal that the Si substrate does not affect the mode of growth. The SE m easurements and TEM observations strongly suggest that TiN rich in nit rogen is formed at nitrogen flow rates in the range 1.9-3 seem. At a n itrogen how rate F-N= 1.7 seem the stoichiometric compound Ti2N is for med which exhibits a completely different mode of growth. The ability of the in-situ SE to monitor small structural changes induced by small changes of the growth conditions was tested by the deposition of sequ ential layers. In this respect SE is a powerful method to control TiN deposition.