When it comes to creating the thin films that manufacturers can use on a whole fleet of different products and applications, there are two main processes: chemical vapor deposition and physical vapour deposition.
Of the many different physical processes that are out there for manufacturers to use, one popular example is electron-beam evaporation (also known as e-beam evaporation).
This is an impressive process that involves heating a material under intense vacuum conditions to release a vapour that moves through the vacuum chamber it was created in and coats a substrate material, thus creating the thin film.
This process is used extensively across many industries and, in this article, we’ll be discussing how the process works in more details and uncover some of it’s most important applications that can improve the way we live our everyday lives.
Electron Beam Evaporation: Overview
E-beam, or electron-beam evaporation is a form of physical vapor deposition that is created using a process that involves bombarding your chosen material with an electron beam that is designed to turn into a vapour.
Once this vapour has been produced, this gives the manufacturer the chance to turn it into a thin film coating on another substrate material.
Along with sputtering, evaporation is one of the most popular forms of physical vapour deposition that has a variety of advantages that can be used across many different applications.
E-beam evaporation has a very high material utilisation efficiency compared to other similar physical processes, which reduces the running costs involved. It also results in a lower degree of contamination as the e-beam only heats the source material, meaning that there is a lower chance of error.
How it Works
Electron-beam evaporation occurs within a vacuum chamber that allows for very high vapour pressures at certain temperatures, which makes it easier for engineers to control the e-beam evaporation system whlie it’s working.
These specific temperatures and pressure also minimises the amount of potential contamination that can effect the deposited thin film on the substrate.
Ultimately, the temperature used during e-beam evaporation needs to be high enough that it can facilitate evaporation and ensure that the material releases a vapour (whether that’s through evaporation or sublimation).
During the process, the material that will be evaporated will be kept on a component known as the source, which will expose the material to a beam of electrons. These electrons are accelerated to a high kinetic energy through a high-voltage electric field of up to 10 kV.
The electrons that are hitting this material are normally released using a process called themionic emission, which comes from a filmement that’s also being held on the source holding the mateiral in place – usually this will be under the material pocket.
The electron beam that’s hitting the material is focussed through a circular profile by a magnetic field and transfers energy into the pocket. During the process, this beam is heating up the material to very high temperatures that cause vapour to be released.
Once the vapour has been released, the source will be water-cooled. This will prevent the chances of co-deposition happening to the source material itself.
The vapour will then be applied to the substrate material in order to make the thin film coating.
Electron-beam evaporation is a very popular method for creating thin films as it allows for much greater temperatures that your usual thermal evaporation processes. Because of this, engineers can use this method to deposit metals on other materials while maintaining a high degree of control over the process.
Evaporant vapour also moves in a straight line between the source and substrate during the process, which creates a a highly anisotropic coating which is useful for a range of different designs, especially lift-off applications.
It’s Many Applications
E-beam evaporation can be used in a variety of applications, which we will discuss further in the following sections.
Metallization is where metal coatings are applied to another metallic or non-metallic surface. Depending on the product or application it’s being used for, the metals that can be used during this process can include zinc, gold, silver or aluminium.
This process can allow for greater weather resistance, reduced maintenance costs, increased durability and enhanced corrosion protection.
This is another term for thin films which relates to sub-micron layers of transparent dielectric materials which are deposited onto a substrate.
Their purpose is to modify the reflective properties of a substrate material, making them often used for laser mirrors and various optical filters.
Optical coatings can be used to describe the process that is used to apply thin films to materials such as glass to alter their optical properties.
The thin film coating will be applied to the glass in extremely thin layers and is usually applied to effet a specific wavelength of light.
Joesephson junctions are devices that are used in a superconducting quantum interference device, also known as SQUIDs.
These devices are used to create extremely sensitive magnetometres and voltmetres.
Why use E-beam Evaporation for Vacuum Coating
E-beam evporation is a process that can be used to deposit a wide range of different materials, especially in the processes used to create optical thin films, solar panels and architectural glass.
The reason why e-beam evaporation is most popular, especially for creating vacuum coatings, is mainly because it has a much higher material utilisation efficiency compared to some other similar physical vapour deposition methods. This is especially important to many manufacturers because it will reduce the costs required.
Where the e-beam is targeted to only heat the source material, the chances of contamination and error are pretty low using this deposition method. Many manufacturers will use programmable sweep controllers that provide optimal heating and advanced control over the process as a whole.
Real-time optical monitoring and control software can also be added to the process, which will create a fully-integrated system for automated control.
Ultimately, e-beam evaporation is a controllable and repeatable process that can enhance the properties of thin films and the substrate materials they are going to coat. The process offers a versatile prospect for production and has the ability to manufacture thin films using high-volume manufacturing techniques.
In terms of creating vacuum coatings, electron beam evaporation can be meet any application’s need and provide effective and versatile benefits.
In this article, we have taken you through what e-beam evaporation is and how it works. This physical vapour deposition process is highly popular at the moment and has applications that can benefit a range of different industries.
Unlike some of the other similar processes, electron-beam evaporation is unique in it’s ability to reduce costs for manufacturers and produce a much smaller margin for error.
Not only can the process be adjusted to allow for more precise control over the very small elements that contribute to the production of highly efficient thin films, but it’s also a repeatable process which can be used to create thin films in a high volume.
The versatility and reliability of this process method is what makes it so popular, and we can expect to continue seeing more industries adapt the method to work for them in the future.