Physical vapour Deposition (PVD) is a family of processes that is used to deposit layers of atoms or molecules from the vapour phase onto a solid substrate in a vacuum chamber. PVD is characterized by a process in which the material goes from a condensed phase to a vapour phase and then back to a thin film condensed phase. The most common PVD processes are sputtering and evaporation.
Difference between Sputtering and E Beam vapour deposition
| S.No. | Sputtering | E beam Vapour Deposition |
| 1. | Sputtering process involves ejecting material from a “target” that is a source onto a “substrate” (such as silicon, quartz wafer etc.) in a vacuum chamber. | This is a process in which a target material is bombarded with an electron beam given off by a tungsten filament (Cathode or high frequency ion source) under high vacuum. |
| 2. | This effect is caused by the bombardment of the target by ionized gas which often is an inert gas such as argon, oxygen, or mixture of Argon and Oxygen etc. | The electron beam causes atoms from the source material to evaporate into the gaseous phase. These atoms then precipitate into solid form, coating everything in the vacuum chamber (within line of sight) with a thin layer of the anode material. |
| 3. | Sputtering is used extensively in the semiconductor industry to deposit thin films of various materials in integrated circuit processing. Anti-reflection coatings on glass for optical applications are also deposited by sputtering. | Due to the very high deposition rate, this process has potential industrial application for wear resistant and thermal barrier coatings aerospace industries, hard coatings for cutting and tool industries, and electronic and optical films for semiconductor industries. |
| 4. | Because of the low substrate temperatures used, sputtering is an ideal method to deposit metals for thin-film transistors. | The material utilization efficiency is high relative to other methods and the process offers structural and morphological control of films. |
| 5. | An important advantage of sputtering is that even materials with very high melting points are easily sputtered while evaporation of these materials in a resistance evaporator is difficult and problematic. | A clear advantage of this process is it permits direct transfer of energy to source during heating and very efficient in depositing pure evaporated material to substrate. Also, deposition rate in this process can be as low as 1 nm per minute to as high as few micrometres per minute. Additionally, coating uniformity and precise layer monitoring techniques are also some advantages with this process. |
Applications of PVD
Making a layer of metals, semiconductors or insulators during device fabrication is very vital and very important step in order to enhance device efficiency, life time and performance. Physical vapour deposition provides the best result in thin film deposition. We can control the deposition rate; we can get better thickness uniformity etc. The main application of PVD now days are in chip manufacturing industry and except of that it has wide range of application and those are as follows
- Semiconductor industry
- Aerospace
- Automotive
- Dies and Moulds for all manner of material processing
- Cutting tools
- Firearms
- Optics
- Watches
- Jewellery