**1. Introduction**

Thin films have been widely used in different application fields such as in chemical as diffusion barrier, in electrochemical as films for protection against corrosion, in mechanical as hard and wear resistance coating, in optical as reflection and antireflection coating, and in electronic area as conductor or insulator material [1–12].

Different chemical elements or compounds have been used to deposit thin films, which have been shown to improve the surface properties of a material (substrate). Among all these compounds, we find that the transition metal nitrides (MeN) have been widely used in mechanical applications due to their high hardness and wear resistance [2, 13–16]. However, it has been found that the addition of a third element may improve the physical and chemical properties of MeN due to a change that this new element generates in the microstructure of these materials [1, 17–30]. These structures are called nanocomposite, and there are two different groups of hard nanocomposite films, for instance: (i) crystalline/amorphous nanocomposites and (ii) crystalline/crystalline nanocomposites.

An element used to improve the properties of MeN is the silicon. In the published literature (**Table 1**), it has been found that the Si addition generated the formation of two phases: a nanocrystalline of MeN and an amorphous phase of silicon nitride (Si3N4), which improved the physical and chemical properties of MeN [17, 19–21,


#### **Table 1.**

*Deposition techniques used for depositing nanocomposites thin films.*

23–25, 28, 31–66]. It has been demonstrated that these nanocomposite thin films have high nanohardness, wear resistance, corrosion resistance, and thermal stability at high temperature. However, the properties of the films depend on the deposition technique and the growth parameters used [4, 8, 10, 13, 26, 67–69].

Among the papers published on nanocomposite films, one of the researchers who has contributed the most in the development of these materials have been Veprek and their co-workers [64, 76]. They have reported the formation of Ti▬Si▬N nanocomposites films with a hardness >40 GPa, which consist of a nanocrystalline phase (TiN) embedded on the matrix amorphous (Si3N4), produced by sputtering magnetron. They found that the decrease in the crystalline size and the formation of two phases (nanocomposite) improve the hardness films to hinder the multiplication and movement of dislocation and the growth of flaws. However, the hardness cannot improve in small nanocrystals about <10 nm, due to the fraction of the material in the increasing grain boundary generates a decrease in the hardness of the film by a grain boundary sliding (Hall-Petch relationship). Therefore, they suggest that an increase on the strength and hardness of the films can be archived with decreasing crystalline size only if grain boundary sliding can be blocked, and this behavior has been shown in different nanocomposite films. Also, they proposed one model to explain the formation of nanocomposite, explaining the phase segregation in Ti▬Si▬N because of spinodal decomposition during deposition. The spinodal decomposition process consists of the reduction of the solubility limit of the silicon on MeN lattice, generating the complete phase segregation of the SiNx around of

**25**

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

the MeN crystals or an increase of the thickness of SiNx amorphous phases [48, 76]. This process is obtained with high temperature (>550°C) deposition and

high quality (homogeneous and dense) and with good adhesion [3, 77, 78].

specifically of nanocomposites formed by zirconium nitride and silicon.

**2. Growth of thin films using DC reactive magnetron sputtering** 

Most publication about nanocomposite films has shown that the DC reactive magnetron cosputtering technique is the most used to deposit these materials (see **Table 1**), and they have reported that the formation and microstructure of the films are determined by the deposition parameters, such as applied power at the target, working pressure, bias voltage, and deposition temperature (see **Table 2**). In a sputtering process, the surface target is hitting with ions produced by an electric discharge, which form plasma. Normally, no reactive gas (Argon-Ar) is used to form the plasma. The interaction of these ions with the surface of the target causes the atoms on the surface to be ripped off through a moment exchange between ions and atoms of the target [4, 77, 79]. These sputtered atoms must transit from target to the substrate surface. During this displacement, the sputtered atoms experience many collisions with the particles that are in this region (sputtered atoms or Ar atoms or reactive atoms in the case of a reactive gas). These collisions change the velocity, direction, and the energy of the sputtered atoms. Therefore, the number of atoms that reach to the substrate surface will depend on the working pressure and the target-substrate distance. Moreover, the formation of the film is related with the condensing energy of the atoms (adatoms) on the surface of the substrate. Different works have found that amorphous films are formed when the adatoms have low energy of diffuse on the surface that does not allow that they may find low energy sites for the nucleation; while, a crystalline structure may be formed when the adatoms have a high surface mobility [8, 15, 80–88]. However, several works have found that when the growing films are exposed to bombardment

The scientific and technologic importance of the development of the nanocomposite films with the chemical and physical performances that those has shown, it is evident if it is considered the great amount the publications that over this theme has been produced. In **Table 1**, it is summarized the most important works of nanocomposite thin films with silicon, as can see, the deposition method most used to deposit these films is sputtering technique. This technique allows to deposit metallic and insulator elements and compounds at low temperature, maintaining the composition of the target. In addition, the films deposited have shown to be of

In this chapter, we discussed about of a new generation of nanocomposite films composed of two phases: a nanocrystalline embedded in an amorphous matrix,

Therefore, the content of the chapter is divided into the following topics: Section 1 is dedicated to describe the more usually experimental deposition conditions of the films via magnetron sputtering techniques. In Section 2 of the chapter will present chemical analysis of their bulk through spectroscopy of the X-ray dispersive (EDX) and the chemical surface analysis of the films by means of spectroscopy of photoelectrons (XPS). Section 3 is dedicated to discuss the influence of silicon in the crystalline structure of the films. This analysis is done through X-ray diffraction (XRD) and transmission electron microscopy (TEM). Sections 4–6 will describe the electrical, optical, and mechanical behavior of the deposited films, respectively. Finally, Section 7 will present the corrosion resistance that gives the films on stainless steel substrates. This analysis will be done with potentiodynamic polarization curves (TAFEL).

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

high nitrogen pressure [64].

**technique**

*Silicon Materials*

**film**

**Table 1.**

**Nanocomposite** 

23–25, 28, 31–66]. It has been demonstrated that these nanocomposite thin films have high nanohardness, wear resistance, corrosion resistance, and thermal stability at high temperature. However, the properties of the films depend on the deposition

Among the papers published on nanocomposite films, one of the researchers who has contributed the most in the development of these materials have been Veprek and their co-workers [64, 76]. They have reported the formation of Ti▬Si▬N nanocomposites films with a hardness >40 GPa, which consist of a nanocrystalline phase (TiN) embedded on the matrix amorphous (Si3N4), produced by sputtering magnetron. They found that the decrease in the crystalline size and the formation of two phases (nanocomposite) improve the hardness films to hinder the multiplication and movement of dislocation and the growth of flaws. However, the hardness cannot improve in small nanocrystals about <10 nm, due to the fraction of the material in the increasing grain boundary generates a decrease in the hardness of the film by a grain boundary sliding (Hall-Petch relationship). Therefore, they suggest that an increase on the strength and hardness of the films can be archived with decreasing crystalline size only if grain boundary sliding can be blocked, and this behavior has been shown in different nanocomposite films. Also, they proposed one model to explain the formation of nanocomposite, explaining the phase segregation in Ti▬Si▬N because of spinodal decomposition during deposition. The spinodal decomposition process consists of the reduction of the solubility limit of the silicon on MeN lattice, generating the complete phase segregation of the SiNx around of

technique and the growth parameters used [4, 8, 10, 13, 26, 67–69].

**Deposition technique**

ZrSiN Unfiltered cathodic arc evaporation [21, 23]

FBR-CVD) [70]

TiSiN Vacuum cathodic arc evaporation [58] zAlSiN DC magnetron sputtering [19, 47, 71]

TiAlSiCuN DC reactive magnetron sputtering [65]

CrZrSiN Unbalanced magnetron sputtering [37] TiSiN-Ag Reactive magnetron cosputtering [25] TaSiN and CrTaSiN Reactive magnetron cosputtering [36, 50] AlTiSiN and CrSiN Cathode arc ion plating system [34, 73]

(PEMS) [38, 74]

TiAlVSiN Vacuum cathodic arc evaporation [58] NbSiN Unbalanced magnetron sputtering [71]

*Deposition techniques used for depositing nanocomposites thin films.*

ZrSiN Hybrid cathodic arc and chemical vapor process [56]

CrSiN Closed field unbalanced magnetron sputtering [75]

ZrTiCrNbSiN Vacuum arc evaporation [31]

TiSiN A combination of DC and RF magnetron sputtering [41, 64]

WSiN DC reactive unbalanced magnetron sputtering [49, 72]

CrAlSiN Cathodic arc evaporation [66]

ZrSiN Reactive magnetron cosputtering [17, 24, 28, 32, 33, 35, 44, 46, 48, 49, 51–55, 57, 59, 63]

TiSiN Chemical vapor deposition in a fluidized bed reactor at atmospheric pressure (AP/

TiSiCN Conventional magnetron sputtering and plasma enhanced magnetron sputtering

**24**

the MeN crystals or an increase of the thickness of SiNx amorphous phases [48, 76]. This process is obtained with high temperature (>550°C) deposition and high nitrogen pressure [64].

The scientific and technologic importance of the development of the nanocomposite films with the chemical and physical performances that those has shown, it is evident if it is considered the great amount the publications that over this theme has been produced. In **Table 1**, it is summarized the most important works of nanocomposite thin films with silicon, as can see, the deposition method most used to deposit these films is sputtering technique. This technique allows to deposit metallic and insulator elements and compounds at low temperature, maintaining the composition of the target. In addition, the films deposited have shown to be of high quality (homogeneous and dense) and with good adhesion [3, 77, 78].

In this chapter, we discussed about of a new generation of nanocomposite films composed of two phases: a nanocrystalline embedded in an amorphous matrix, specifically of nanocomposites formed by zirconium nitride and silicon.

Therefore, the content of the chapter is divided into the following topics: Section 1 is dedicated to describe the more usually experimental deposition conditions of the films via magnetron sputtering techniques. In Section 2 of the chapter will present chemical analysis of their bulk through spectroscopy of the X-ray dispersive (EDX) and the chemical surface analysis of the films by means of spectroscopy of photoelectrons (XPS). Section 3 is dedicated to discuss the influence of silicon in the crystalline structure of the films. This analysis is done through X-ray diffraction (XRD) and transmission electron microscopy (TEM). Sections 4–6 will describe the electrical, optical, and mechanical behavior of the deposited films, respectively. Finally, Section 7 will present the corrosion resistance that gives the films on stainless steel substrates. This analysis will be done with potentiodynamic polarization curves (TAFEL).
