Nevertheless, this deduction needs to be verified from HRTEM observations. Figure 2 presents the typical cross-sectional HRTEM images of TiN/SiN x film with Si/Ti selleckchem ratio of 4:21 and TiAlN/SiN x film with Si/Ti0.7Al0.3 ratio of 3:22. From Figure 2a,c, it is clear that similar with TiN and TiAlN monolithic films, both nanocomposite films show obvious columnar growth structure, in agreement with results from Zhang et al. [7] and Kauffmann et al. [8]. This columnar growth structure
cannot be explained by the nc-TiN/a-SiN x model. According to the model [4, 14], with the addition of Si AZD8931 element, the amorphous SiN x interfacial phase interrupted the columnar growth of TiN and divided into many equiaxed TiN nanocrystallites. In this case, the columnar cross-sectional morphology should not be observed, but the amorphous fracture morphology as presented in [15]. However, the columnar cross-sectional structure is obviously observed in both TiN/SiN x and TiAlN/SiN x films, which brings further question to nc-TiN/a-SiN x model. Figure 2 Cross-sectional HRTEM images of TiN/SiN x and TiAlN/SiN x nanocomposite films.
(a) Low magnification, (b) medium magnification, (d) high magnification for TiN/SiN x nanocomposite Dinaciclib ic50 film (Si/Ti = 4:21), and (c) low magnification, (e) high magnification for TiAlN/SiN x nanocomposite film (Si/Ti0.7Al0.3 = 3:22). The SiN x interfacial PLEKHB2 phase is observed to exist as crystallized state, rather than amorphous state, such as E zone between A and C crystals, F zone between A and B crystals, H zone between B and D crystals, and G zone between C and D crystals. From Figure 2a, it can also be seen that many small equiaxed nanocrystallites exist within the TiN/SiN x film in the cross-sectional morphology. In the medium-magnification
image of Figure 2b, it is obvious that many equiaxed nanocrystallites with dark contrast are surrounded by the interfacial phase with bright contrast. According to the nanocomposite structure of TiN/SiN x film, it is not difficult to conclude that the equiaxed nanocrystallites with dark contrast and interfacial phase with bright contrast correspond to TiN and SiN x phases, respectively, indicating that the film constituted of equiaxed TiN nanocrystallites encapsulated with SiN x interfacial phase, rather than columnar-like TiN nanocrystals proposed by Kong et al. [5]. The average size of TiN crystallite is about 6 to 10 nm, with average SiN x interfacial thickness of 0.5 to 0.7 nm. In the high-magnification image of Figure 2d, the TiN crystallites basically grow along with the same direction and present the epitaxial growth structure.