Sputtering is a useful source due to its lack of reliance on vaporisation temperature, therefore, materials with very high melting points are mainly deposited via sputtering. It also can be used to produce compound films through a process known as reactive sputtering.

E-beam evaporation has a higher deposition rate and excellent uniformity and is popular in the aerospace, tool manufacturing, and semiconductor industries. Though it can produce high temperatures, it is limited by certain materials.

Evaporation: Overview and Applications

Most physical vapour deposition (PVD) evaporation systems use an electron beam to bombard a tungsten substrate or other materials in a vacuum chamber or a resistive heat source to vaporise the material, allowing it to settle over a substrate to form a thin film coating. However, these evaporation methods have several differences.

Thermal Evaporation by Resistive Heating

In resistive thermal evaporation, the target material is placed in a boat or crucible in a resistive electrical coil. The coil/boat receives a high current, heating the crucible and in doing so, the material. The material heating in the vacuum chamber vaporises and then condenses to coat the substrate, as in the Korvus TES thermal boat system.

Review thermal evaporation explained in more depth, and learn more about the TES here.

Electron Beam Evaporation

E-beam evaporation uses an electrons emitted through thermionic emission to bombard and heat a target directly, or a crucible. This brings the source material to its gaseous form to then create thin films through its condensation onto a substrate. Learn more about the TAU E-Beam source and how it differs from typical electron evaporation.

Low Temperature Thermal Evaporation

In low temperature evaporation, resistive thermal evaporation or e-beam evaporation is balanced with a cooling source around the boat for precise control of the evaporation and deposition rate. This is achieved in the Korvus ORCA through a PID thermal feedback loop and computer-controlled heating and cooling balance.

Pros and Cons of Evaporation

Each evaporation method to deposit thin films onto a substrate has benefits and disadvantages.

Pros:

Suitable for a wide range of sources and excellent for applications over electrical contacts

• High deposition rate
• Excellent uniformity when using masks or planetary
• Electron beam evaporation is good for materials with high melting points
• E-beam evaporation offers high throughput
• Can be a more simple and cost effective option (thermal evaporation)

Cons:

• Poor uniformity without planetary or masks
• Moderate system complexity in electron beam evaporation

Sputtering: Overview and Applications

Sputtering is another PVD process that uses ionised gas in processes such as ion beam sputtering, reactive sputtering, plasma sputtering, and other types of magnetron sputtering to produce high-quality films.

Sputtering offers high deposition rates and volume production, including thin film application in semiconductor circuits, thin film transistor parts, anti-reflective glass coatings for eyeglasses, and low-e architectural glass coatings.

In magnetron sputtering, a plasma-based coating method, positively charged ions from magnetically confined plasma collide with negatively charged target material, sputtering off the target material which then moves through the chamber and condenses onto the substrate. This offers the highest scalability of any PVD process.

Learn more about the sputtering process here, and discover the benefits of the FISSION Sputtering source.

Pros and Cons of Sputtering

Sputtering methods to deposit thin films onto substrates come with their own pros and cons.

Pros:

• High deposition rate
• Moderate to high stress film density
• High throughput
• Highest uniformity in ion beam sputtering (IBS), good uniformity in magnetron sputtering
• Highest quality films using IBS
• Magnetron sputtering is excellent for dense films, strong adhesion to the substrate, film deposition for optical applications and electrical parts, and automated applications
• IBS is ideal for high-quality film deposition when control over stoichiometry or film thickness is essential

Cons:

• Poor deposition rate for dielectrics
• High system complexity and high cost
• Energised vapour material can cause substrate heating
• Low deposition rates for IBS

Which To Choose?

How do you know which method to choose: evaporation or sputtering? Evaporation is more cost effective and less complex. Additionally, evaporation offers higher deposition rates, allowing for high throughput and high-volume production. In contrast, sputtering offers better film quality and uniformity, potentially leading to a higher yield. It also offers scalability, although at a higher cost and with more complex setups.

For thicker metallic or insulation coatings, sputtering may be the better option. For thinner films of metals or nonmetals, resistive thermal evaporation may be better for film materials with lower melting temperatures. Electron beam evaporation could be the right choice for improved step coverage or if working with a wide selection of materials.

Choose Korvus Technology for Physical Vapour Deposition Systems

At Korvus Technology, we offer the HEX Series PVD system with several customisation options for it to function as a sputtering system, as well as e-beam, thermal evaporation and organic evaporation for applying thin films under carefully controlled parameters. Contact us today to learn more about our systems and decide whether evaporation vs sputtering is right for you.

References

[1] Donald M. Mattox (2010). Chapter 1 – Introduction, Handbook of Physical Vapor Deposition (PVD) Processing (Second Edition), 1-24, DOI: 10.1016/B978-0-8155-2037-5.00001-0

[2] M. R. Rashidian Vaziri, F. Hajiesmaeilbaigi, M. H. Maleki; Monte Carlo simulation of the subsurface growth mode during pulsed laser deposition. Journal of Applied Physics 15 August 2011; 110 (4): 043304. https://doi.org/10.1063/1.3624768

[3] Martin, P.J. Ion-based methods for optical thin film deposition. J Mater Sci 21, 1–25 (1986). https://doi.org/10.1007/BF01144693

[4] Ghazal, H., & Sohail, N. (2023). Sputtering Deposition. IntechOpen. doi: 10.5772/intechopen.107353