Understanding Thin Film Technology: Process, Purpose

Thin film technology: Do you know what thin films are? Are you curious about how they’re used in today’s world?

You may not perceive them often, but they play a crucial role in the different comforts you’ve come to enjoy and experience every day, from the lenses of your glasses to your mobile device.

A thin film is a layer of material with a thickness ranging from a nanometer (monolayer) to a few micrometers (multilayer).

It is produced using various deposition techniques, particularly physical and chemical vapor deposition, and is widely used across multiple industries.

In the biomedical industry, thin films help produce artificial limbs, implants, and implantable sensors. In the aerospace industry, they help protect windows and windshields from rust and other malfunctions with their high erosion resistance.

If you want to know more about thin film technology, you’re on the right page. This post tackles different topics about thin films, including the process behind them, their applications, etc. Keep reading below to learn more.

How Are Thin Films Produced?

Thin films are produced through thin film deposition. This process creates and applies layers of thin films to a substrate. Such layers can be made using different materials like metals, oxides, and other compounds.

Thin film deposition plays an essential role in manufacturing medical devices, consumer electronics, LED displays, semiconductors, fiber lasers, etc. Without thin films, these pieces of technology won’t be able to become what they are today.

There are two types of thin film deposition: physical vapor deposition and chemical vapor deposition.

1. Physical Vapor Deposition (PVD)

In PVD, there are two basic processes involved. First, there will be vaporization of solid matter in a vacuum, which produces a thin film. Second, the thin film produced earlier will be applied to a substrate.

PVD-made coatings are guaranteed to be highly durable, scratch-resistant, and corrosion-resistant. Such characteristics make them useful in manufacturing various devices, from eyeglasses to semiconductors and solar cells.

There are four different types of PVD:

  • Evaporation: In this process, solid matter is evaporated using an electron beam, which is then deposited onto a substrate, creating thin films. This is often applied to solar panel production.
  • Magnetron Sputtering: In this process, magnetic plasma is created near the solid matter. Its ions collide with the solid matter, ejecting atoms (sputtered atoms) that are deposited onto a substrate, creating thin films.
  • Pulsed Laser Deposition (PLD): In this process, solid matter is evaporated using laser pulses. This produces plasma that is deposited onto a substrate, creating thin film coatings.
  • Ion Beam Sputtering (IBS): Also known as ion beam deposition (IBD), this sputters ions onto a solid matter, creating thin films. Because of its high precision, IBS is often performed when producing semiconductors and precision optics.

Among these PVD types, magnetron sputtering is arguably the most expensive but more scalable than others.

2. Chemical Vapor Deposition (CVD)

CVD vaporizes two chemical precursors by heating them. When they reach the surface of a substrate, chemical reactions take place, forming high-quality thin film coatings.

These coatings are useful in the production of automotive components, silicon wafers, and medical devices.

There are four different processes under the CVD umbrella:

  • Atmospheric Pressure CVD: In this process, there’s at least one volatile precursor to which a substrate is exposed. This creates a reaction, creating low-density thin film coatings.
  • Low-Pressure CVD: In this process, heat breaks down a gas precursor, causing it to react with a substrate once introduced into the chamber. This produces more uniform thin film coatings with slight defects.
  • Atomic Layer Deposition (ALD): In this process, continuous pulses vaporize gas precursors, forming a thin film. It’s done simultaneously until the desired thickness is achieved. ALD-produced thin films are defect-free and more uniform than others.
  • Ultrahigh Vacuum CVD: In this process, substrates are exposed to gas precursors inside a high-vacuum chamber. This creates a reaction, which forms a thin film coating.

It’s important to note that CVD can work on different kinds of substrates, making it ideal for coating intricate topographies. Plus, CVD-made thin films can maintain their bonds even in volatile environments.

What Is The Purpose Of Thin Film Technology?

Thin film technology is widely utilized by different industries for many purposes. It can be used to create reflectivity on lenses, build layers on semiconductors, and protect delicate screens from scratches.

The thin film market includes optoelectronics, semiconductors, and healthcare.

1. Optoelectronics

Common applications of thin films in optoelectronics include LED and OLED displays, consumer electronics, laser diodes, fiber lasers (metal cutting), and fiber optic lasers (telecom systems). These industries use various coatings, including:

  • Anti-Reflectivity/High-Reflectivity (AR/HR) Coating: This coating is ideal for solar cells, photographic lenses, and other devices.
  • Indium Bump: This coating is primarily used in infrared imaging. It has high shear strength, collimation control, and good lift-off.
  • Optical Filter: This is similar to AR/HR but filters light through optics, making it useful in photolithography, image splitting, Raman spectroscopy, and image enhancement.

Other coatings commonly used in optoelectronics are transparent conductive oxides (TCO) and diamond-like carbon (DLC) coatings. Both are widely used to protect screen displays.

2. Semiconductors

Semiconductors require specific thin film coatings to conduct electricity and allow data storage and transmission. These coatings include metallization, DLC coating, contact coating, barrier overcoats, precision alloys, and gold coating.

Typical applications of thin films in semiconductors are as follows:

  • LED displays
  • Photodetectors
  • Focal plane arrays
  • Radiofrequency power transistors
  • Infrared detectors

Most of these applications need a significant volume for mass production purposes.

3. Healthcare Applications

In the healthcare industry, thin films are used to protect and increase the integrity of medical implants, artificial limbs, and other similar devices.

Thin film coatings have to be precise and high quality to meet the medical standards specified by the FDA and other bodies. Typical coatings used in the production of medical devices include DLC and biocompatible hard coatings.

Biocompatible Hard Coatings (BHC) are produced using titanium aluminum nitride, titanium nitride, titanium carbo-nitride, or chromium nitride. These coatings help prolong the shelf-life of medical implants and improve the stability of implantable prostheses.

Final Thoughts

Thin film technology plays an essential role in the production of various devices. These include consumer electronics, fiber optic lasers, medical devices, transistors, and semiconductors. Without thin films, the products everyone enjoys won’t be as capable as they are today.

In this article, we have discussed the process of thin film technology in simple words. Hope that you will have understood the basic points about thin film and enjoyed it. If you like this article, please share it on the social networking sites with love.
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