1、Background of TiN Film Applications

With the development of modern science and technology, the application of thin film materials is becoming more and more widely. Titanium nitride (TiN) films are excellent for surface modification due to their hardness, wear resistance, chemical stability, thermal stability, low resistivity, and distinctive golden yellow color, making them suitable for coatings, microelectronics, and medical applications.

2、Structure and properties of TiN films

Ti and N can form a variety of solid solutions and compounds, common Ti-N compounds have Ti₂N and TiN two, the metal titanium (Ti) in theinterstitial phase is a dense row of hexagonal dot matrix or face-centered cubic dot matrix arrangement, non-metallic nitrogen (N) atoms fill the interstitial position in the Ti crystals. Ti2N structure, the metal Ti atoms are arranged in dense rows of hexagonal dotted line, and the N atoms in the gap position; TiN structure, the metal Ti atoms are arranged in face-centered cubic dots, N atoms in the octahedral gap position.

The crystal structure of the TiN film is shown in Fig. This belongs to the face-centered cubic structure of the NaCl type. In this structure, Ti atoms occupy the fcc (face-centered cubic) lattice positions, while N atoms occupy the octahedral interstitial positions of the fcc lattice. The lattice constant of the film at room temperature is a = 0.424 nm, the slip system is {110}<110>, and the theoretical value of density is 5.339 g/cm³

Figure 1. Schematic of Titanium nitride film crystal structure

3、Application of FRINGE for grazing incidence X-ray diffraction for Titanium nitride film

X-ray testing techniques are commonly used to characterize thin film materials, which depend on their substrate. In conventional X-ray diffraction (XRD) testing, the X-ray penetration depth often exceeds the film's thickness, causing the substrate's strong signals to obscure those of the film.

In addition, as the diffraction angle increases, the area of X-rays irradiating the sample gradually decreases. Consequently, the X-rays can only penetrate a portion of the sample, and can not utilize the entire sample volume, thus results in a weak diffraction signal.

Figure 2. Left) Schematic diagram of grazing incidence X-ray diffraction (GIXRD) of thin films and right) FRINGE installation test diagram

4、Experimental Case

In this experiment, a FRINGE desktop X-ray diffractometer from LANScientific was used to detect the GIXRD of a wafer TiN film sample (60 nm TiN/400 nm SiO₂/Si) provided by an enterprise.

（1）Sample display

Figure 3. Actual picture of a company's wafer TiN film sample

Left image - High film processing temperature, labeled 1#-TiN film.

Right image - Film processed at lower temperature, labeled 2#-TiN film.

（2）Test parameter setting

(3) Results & Conclusions

Figure 4. Diffraction pattern of thin film sample 1#-TiN film (single crystal silicon substrate)

 in the θ-θ scanning mode of powder diffraction

Figure 5. Explanation of the abnormal peaks on the diffraction pattern of 

thin film sample 1#-TiN film (single crystal silicon substrate) in the θ-θ scanning mode of powder diffraction

Table 1

Figure 6. Diffraction pattern and qualitative results of 

thin film sample 1#-TiN film in film swept scanning mode

Figure 7. Diffraction pattern and qualitative results of 

thin film sample 2#-TiN film in film swept scanning mode

Figure 8. Overlay diffraction pattern of 

film samples 1# and 2#-TiN film in film swept scanning mode

(4) Conclusions of analysis

1) Two diffraction geometries were used for testing samples. In the conventional symmetric diffraction geometry (CXRD), the sample is fixed while the X-ray tube and detector rotate through the θ angle. In the grazing-incidence asymmetric diffraction geometry (GIXRD), the sample and light pipe remain stationary, with X-rays directed at a fixed angle of 1°, while the detector scans a wide angular range of 2θ to collect diffraction signals (Fig. 2).

2) Figure 4 shows the diffraction pattern of a TiN film on a single crystal silicon substrate in θ-θ scanning mode. The 400 diffraction peak at 69.2° (2θ) appears as  due to distortion from strong diffraction intensity. Figure 5 explains the abnormal peaks in the 1#-TiN film's diffraction pattern, with one peak near 33° corresponding to the Si(002) crystal surface.

3) The diffraction patterns and qualitative results of Film 1#-TiN and Film 2#-TiN in grazing incidence scanning mode are presented in Figs. 6 and 7. It is evident that the material phase of both wafer films, treated at different temperatures, consists entirely of titanium nitride with a face-centered cubic structure, as indicated by PDF card number 00-038-1420. Additionally, card matching reveals a selective (200) orientation in Film 2#-TiN.

4) The stacked diffraction patterns of films 1# and 2#-TiN in the swept scanning mode are presented in Fig. 8. It is evident that the diffraction peaks of film 1#-TiN, which was treated at a higher temperature, are sharper than those of film 2#-TiN. This indicates that the crystallinity of film 1#-TiN is superior. The crystallinity of both films was calculated using a split-peak fitting program. As shown in Table 1, the crystallinity of film 1#-TiN is 57%, while film 2#-TiN is 36%. This result aligns with the post-treatment temperatures of the films.

5、Conclusion

Suzhou FRINGE desktop X-ray diffractometer from LANScientific, with film accessories, analyzes film samples' physical phases, crystallinity, and grain size. GIXRD provides strong data support for material research, production, and quality control, enabling timely process adjustments for high-quality products.