**3.3 Plasma-enhanced chemical vapor deposition (PECVD)**

The PECVD technique is a form of CVD, which uses plasma to enhance/enable the reactivity of organic/inorganic chemical monomers for the deposition of thin films. In this technique, it is possible to use precursors in solid, liquid, or gaseous form for

**Figure 3.** *Sample and cathodic cage arrangement over the sample holder [29].*

#### **Figure 4.**

*(a) Visual aspect of plasma formation on the surface of the cage. and (b) Example of arrangement for treatment by CCPD (graphite cylinder and Ti cover).*

the deposition of thin films [31]. The precursors are typically decomposed by temperature or a combination of temperature and plasma chemistry [32].

In conventional CVD processes, high treatment temperatures are used and the use of plasma by PECVD technique activates the chemical vapor precursor, and it allows the deposition to progress at a lower temperature than is normally used for CVD [32].

A schematic representation of the standard PECVD thin film deposition process is shown in **Figure 5**.

The advantages of this technique include highly cross-linked, uniform, robust films with good surface adhesion; compatible with solid, liquid, and gas monomers; leading to higher deposition rates and high density of cross-linking; working with low and atmospheric pressures. As a disadvantage, this technique may suffer from high internal stresses, which can cause film delamination. This technique can be used for highly cross-linked, uniform, robust films with good surface adhesion; corrosion and wear resistance; deposition of various types of materials with different microstructures [31–34].

#### **Figure 5.** *Schematic representation of a standard chamber used in the PECVD process [31].*
