## 3 Results and Discussion  
Figure 2 shows the diffraction pattern, FWHM, grain size, and residual stress of the TiN thin film with respect to the change in substrate temperature. The lattice deformation of the TiN thin film was preferentially measured by the 4-fold circle XRD method using the glancing angle XRD. In Figure 2a, the XRD diffraction measured in the range of 20 = 10\({}^{\circ}\) to  
Figure 1: SEM cross-sectional image of the TiN thin film deposited with a substrate temperature variation: the thicknesses of the thin films deposited at ambient temperature, 100, 200, and 300 \({}^{\circ}\)C are (a) 311 nm, (b) 222 nm, (c) 228 nm, and (d) 282 nm, respectively. \(100^{\circ}\) by scanning at \(2^{\circ}/\min\) shows the diffraction pattern of the TiN thin-film deposited at different substrate temperatures--ambient, 100, 200, and 300 \({}^{\circ}\)C. Although several different phases (Ti\({}_{3}\)N\({}_{2}\), Ti\({}_{4}\)N\({}_{3}\), TiN, Ti\({}_{2}\)N) exist, as shown in Figure 2a, peaks in the (111) and (222) directions are observed in the TiN thin film with FCC preferential growth characteristics. In addition, different from other phases in the color of the TiN thin film, the stoichiometry TiN (fcc) surface exhibited a golden color, which is a unique color. This result was consistent with the results of a previous study [24]. The crystal plane of the (111) plane grows according to the change in the substrate temperature, whereas the (222) plane has a relatively low peak intensity and wide FWHM, which indicates that it is a metastable phase close to the amorphous phase. The FWHM value in the main crystal growth direction (111) and grain size were calculated using the Scherer equation to evaluate the FWHM value and grain size of the diffraction peak of the TiN thin film. The Scherer equation is given as [7; 13; 14]. \[\text{D}=\frac{0.9\lambda}{\beta\cos\theta} \tag{1}\]  
where \(\lambda\), \(\beta\), \(\text{D}\), and \(\theta\) denote the wavelength of the X-ray, value of the half width, grain size, and Bragg angle of the (111) peak, respectively; the calculation results are as shown in Figure 2b. Figure 2: XRD measurement results of the TiN thin film deposition at the varying substrate temperature: (**a**) XRD patterns; (**b**) FWHM and grain size change; (**c**) residual stress change. The FWHM decreased with an increase in the substrate temperature, and the grain size increased with a decrease in the FWHM value. In terms of the grain size of the TiN thin film, the FWHM in the (111) direction became narrow with an increase in temperature, and the intensity of the peak increased, which increased the grain size. The crystal structure is deformed and the lattice spacing changes in a material with residual stress. That is, the strain rate can be obtained through the change in the interplanar spacing of the crystal lattice; this is formulated as:  
\[e=\frac{\text{d}-\text{d}_{0}}{\text{d}_{0}} \tag{2}\]  
where d and d\({}_{0}\) represent the spacing between the lattice planes with and without residual stress on the specimen, respectively. \(\psi\) diffraction is performed to rotate the crystal according to the diffraction condition because only the plane parallel to the thin film participates in diffraction; the interplanar distance of the same planes with different crystal directions is obtained by measuring the XRD in a specific 2\(\theta\) range. The \(\psi\) angle and face distance presents a linear relationship by plotting sin2\(\psi\) to 2\(\theta\)(d); the sin2\(\psi\) method is used to calculate the residual stress through the slope. The stress can be obtained using Hooke's law by measuring the grid spacing at each location; the residual stress is measured based on the (111) direction and the growth direction of the TiN thin film. The results are shown in Figure 2c. The residual stress decreased with an increase in the substrate temperature.