Physical Vapor Deposition Techniques
摘要
In this chapter, different physical vapor deposition techniques have been discussed. Mostly, all the techniques were based on the same principle which is the conversion of the condensed phase to the vapor phase and then back to the condensed phase. This conversion involves different steps that are critical and vary from technique to technique. A vacuum chamber is needed along with a cathode and anode with a source and substrate. The anode and cathode are attached inside the chamber. The vacuum is generated inside the chamber by different pumps. The source is attached through which coating is done on the substrate. Mostly substrate is attached to the anode and the source with the cathode. The source position may vary in different equipment. After creating a vacuum, the process starts, which involves the heating process, vaporization, sputtering, ionization, and laser techniques. These steps vary in different equipment. Then, the thickness of the coating is checked through a quartz crystal. The quartz crystal is a sensitive material through which thickness is measured. Different techniques involve the thermal evaporation process, sputtering, pulsed laser ablation, and ion plating. The sputtering is further divided into DC and RF sputtering. The oldest technique is the evaporation process, the sputtering technique was invented due to high voltage and melting point. But this also generates the secondary electrons due to which the thin film generated is not good in quality. So, for that purpose, DC and RF sputtering techniques were invented, which is also known as magnetron sputtering. As with the technology advancement, the pulsed laser ablation was introduced in which the laser’s high power, intensity, and diameter determine the thin-film patterning and coating. Finally, ion platting was invented which is similar to sputtering but is quite better than sputtering. All the processes have their advantages and disadvantages in daily life applications and processes. Every process has limitations also which is discussed in this chapter. Furthermore, the complete process, working principle, construction, advantages, and disadvantages are also discussed.