**3. Chemical characterization by means of spectroscopy of the X-ray dispersive (EDX) and spectroscopy of photoelectrons (XPS)**

In the sputtering technique, the elements of target are transferred to the substrate surface; this is verified with EDX analysis. **Figure 1a** shows the EDX spectrum for the ZrN + 2Si film.

The EDX spectrum evidences the presence of zirconium, nitrogen, and silicon in the film. The elemental chemical composition of the deposited films is listed in **Table 4**. **Figure 1b** shows the variation of the zirconium content with the increase of the silicon content in the films. As silicon content increases, the Zr content decreases in the films due to the reduction of the effective sputtering area of the Zr target with the Si pellets. These results are similar to those published by other authors using the same sputtering configuration [59, 62, 92]. The EDX results also showed that with one Si pellet, the Si content was of 8 at.% and with two pellets was of 15 at.%.

It has been found that when the solubility limit of Si in MeN lattice is exceeded, the Si atoms form a Si3N4 phase [94]. The formation of Si3N4 phase into MeN grain boundaries is typical for the Me▬Si▬N systems [17, 19, 25, 41, 71, 73]. Therefore, in our case, a chemical analysis for XPS of the ZrN▬Si deposited films with different Si contents was carried out to show the formation of the Si3N4 phase with the Si addition. **Figure 2** shows the high-resolution XPS spectrum for the MeN films. The XPS results of Zr 3d peaks (**Figure 2a**) showed the presence of Zr▬N bond with a binding energy of 179.6 eV [95], and the Si 2p peaks (**Figure 2b**) showed the presence of Si-N bond to 100.8 eV [24] on the film surface. Additionally, the results

#### **Figure 1.**

*(a) EDX spectrum of ZrN + 2Si film with a 15 at.% of silicon and (b) the stoichiometry behavior of the ZrN*▬*Si deposited film at different silicon contents.*


#### **Table 4.**

*The elemental chemical composition of the deposited films with different Si contents.*

#### **Figure 2.**

*High-resolution XPS spectra for ZrN*▬*Si films with different silicon contents (a) Zr 3d and (b) Si 2p. The Si addition generated the formation of the Si3N4 phase in the films.*

showed the formation of zirconium oxide (ZrO2) and oxynitride of zirconium (ZrOxNy) that can be due to the presence of residual oxygen in the deposition chamber and to high possibility that has the zirconium to react with oxygen according to enthalpy of formation for ZrO2 that is −1101.3 kJ/mol [96].

Various works have shown that the Si exists as solid solution in the ZrN lattice up to 3.0 at.%, but when the Si content increases, the formation of the Si3N4 phase is observed [17, 21]. Therefore, the EDX and XPS results show that with a Si content of 8 at.%, the solubility limit of Si in ZrN lattice is exceeded, generating the formation of Si3N4 into ZrN grain boundaries with the increased Si content, probability of the volume of the phase of Si3N4 is increased, and the phase of ZrN is decreased.

**29**

**Figure 3.**

*Effect of Silicon Content in Functional Properties of Thin Films*

With a high Si content (15 at.%), the film is amorphous.

(pdf. 00-050-1089) and Si3N4 (pdf. 00-033-1160).

*The XRD patterns of the ZrN*▬*Si films with different silicon contents.*

**4. Structural characterization of the films through X-ray diffraction** 

With the addition of Si, it has been found that the microstructure of MeN films changes, and this change will depend on Si. Three types of microstructure have been observed in function of Si content: polycrystalline films with low Si content up to 3 at.%, nanocrystalline films with 3–10 at.% (nanocomposite: nanocrystalline and amorphous phase), and with a Si content above 10 at.%, the films are amorphous. These values on the silicon content are obtained for Ti▬Si▬N deposited films with different Si contents [97], but may change

depending on MeN. In our case, the microstructure ZrN▬Si deposited films were characterized by XRD and TEM techniques. **Figure 3** shows the XRD pattern of ZrN films with different Si contents deposited on the common glass substrate. **Figure 3** exhibits diffraction peaks corresponding to fcc-ZrN (pdf. 01-078-1420) for the ZrN film without silicon (black color). The addition of Si, red and blue color, indicates that the diffraction peak of the ZrN (111) tends to broaden, while the ZrN (200) peak disappears as Si content increased. The broadening of the peak may be due to the formation of nanocrystals of cubic ZrN and tetragonal ZrO2, reported in the 2θ position 33.83° (pdf. 01-078-1420) and 30.27° (pdf. 00-050-1089), respectively. The crystalline size for ZrN films is <10 nm, which was determined for the Scherrer equation, and with the addition of Si, the crystalline size decreased until 5 nm. The XRD evidenced that Si addition generated a refinement of grain, which is related with a broadening of the diffraction peaks.

To study the structure of the ZrN▬Si film with Si content of 8 at.% in more detail, transmission electron microscopy with selected area electron diffraction (SAED) was done. **Figure 4** shows the SAED pattern of ZrN + 1Si film. It shows the presence of the (111), (200), and (220) diffraction rings, which indicate a fcc-ZrN structure, but the (111) diffraction ring is very broad, which is in very good agree-

In addition, this ring broadens may be related with a mixture of phases, such as: ZrN, ZrO2 and Si3N4 as we can see in **Figure 5**. This figure shows the XRD pattern of ZrN + 1Si film and the crystallographic databases for ZrN (pdf. 01-078-1420), ZrO2

ment with the XRD results in the same d-spacing from 0.295 to 0.262 nm.

**(XRD) and transmission electron microscopy (TEM)**

*DOI: http://dx.doi.org/10.5772/intechopen.85435*

*Silicon Materials*

**Figure 1.**

**Table 4.**

*ZrN*▬*Si deposited film at different silicon contents.*

**28**

**Figure 2.**

*High-resolution XPS spectra for ZrN*▬*Si films with different silicon contents (a) Zr 3d and (b) Si 2p. The Si* 

Various works have shown that the Si exists as solid solution in the ZrN lattice up to 3.0 at.%, but when the Si content increases, the formation of the Si3N4 phase is observed [17, 21]. Therefore, the EDX and XPS results show that with a Si content of 8 at.%, the solubility limit of Si in ZrN lattice is exceeded, generating the formation of Si3N4 into ZrN grain boundaries with the increased Si content, probability of the volume of the phase of Si3N4 is increased, and the phase of ZrN is decreased.

showed the formation of zirconium oxide (ZrO2) and oxynitride of zirconium (ZrOxNy) that can be due to the presence of residual oxygen in the deposition chamber and to high possibility that has the zirconium to react with oxygen according to

*(a) EDX spectrum of ZrN + 2Si film with a 15 at.% of silicon and (b) the stoichiometry behavior of the* 

ZrN 51.0 49.0 0.0 ZrN + 1Si 43.0 49.0 8.0 ZrN + 2Si 36.0 49.0 15.0

**Zirconium (Zr) Nitrogen (N) Silicon (Si)**

**Samples name Atomic percentage (at.%)**

*The elemental chemical composition of the deposited films with different Si contents.*

*addition generated the formation of the Si3N4 phase in the films.*

enthalpy of formation for ZrO2 that is −1101.3 kJ/mol [96].
