WNX FILMS PREPARED BY REACTIVE ION-BEAM SPUTTER DEPOSITION

WNx thin films (0.5 less-than-or-equal-to x less-than-or-equal-to 1) were deposited at room temperature on clean silicon substrates by reactive ion-beam sputter deposition in an UHV set-up. Properties such as morphology, microstructure, density, composition, mechanical stress and resistivity have been investigated as functions of ion-beam energy. Thermal stability of very thin films during sequential annealings and Schottky diodes were respectively characterized by in situ Auger electron spectrometry and C(V) measurements. It is demonstrated that a subnitridation of the silicon substrate occurs during the initial growth of the WNx layers. This may explain the absence of silicon out-diffusion up to more than 700-degrees-C and some anomalies observed during the electrical measurements of the Schottky diodes.