can be seen that two series of films are only composed


can be seen that two series of films are only composed of TiN or TiAlN phase, while AZD8931 chemical structure no SiN x phase is detected. Veprek had attributed the absence of SiN x phase to its amorphous characteristic [4]. buy SC79 Actually, it can also be explained by low content of SiN x phase. Figure 1a,b indicates that TiN/SiN x and TiAlN/SiN x nanocomposite films both present (200) preferred orientation. With the increase of Si content, the intensities of TiN and TiAlN (200) diffraction peaks firstly increase and then decrease, suggesting that the crystallinity for TiN and TiAlN phases initially improves and then deteriorates. The TiN/SiN x and TiAlN/SiN x films exhibit the highest crystallinity when Si/Ti (or Si/Ti0.7Al0.3) ratio is 4:21 and 3:22, respectively. Figure 1 XRD patterns of (a) TiN/SiN x and (b) TiAlN/SiN x nanocomposite films with different Si content. The influence of Si content on crystallinity throws doubt upon the nc-TiN/a-SiN x model proposed by Veprek [3, 4]. If SiN x phase exists as amorphous state, the increase of Si/Ti ratio from 1:24 to 5:20 (SiN x fraction

accordingly rises from 4 to 20 at.%) only leads to thickening of amorphous SiN x interface, which cannot improve the crystallization degree of film, but lowers it due to the increasing impeditive effect AICAR manufacturer on TiN growth. In addition, as amorphous SiN x interfacial phase thickens, TiN and TiAlN phases cannot only present (200) orientation, but may also grow along other directions owing to the randomicity of isothipendyl crystallite growth [10]. Therefore, whether SiN x interfacial phase

is amorphous deserves to be further deliberated. In fact, the effect of Si content on crystallinity of TiN/SiN x and TiAlN/SiN x films brings into our mind the influence of amorphous modulation layer thickness on the crystallization degree of nanomultilayered films, such as TiN/SiC [11], TiAlN/SiO2[12], and CrAlN/SiN x [13]. In these nanomultilayered film systems, with the increase of amorphous layer thickness, the crystallization degree of films firstly increases and then decreases, which can be attributed to two facts. On one hand, the initial increase of amorphous layer thickness could not only crystallize the amorphous layer and grew epitaxially with crystal layer, but also the newly deposited crystal layer could grow epitaxially on crystallized amorphous layer, leading to the ‘mutual promotion effect’ of growth in nanomultilayers and improvement of crystallization integrity. The thicker the crystallized amorphous layer thickness is, the higher the crystallization degree of the nanomultilayered film. On the other hand, with further increase of amorphous layer thickness, the amorphous layers cannot keep the crystallization state and change back into the amorphous state, which destructs epitaxial growth structure and decreases the crystallization integrity of the nanomultilayer.

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