With smartphones and display screens being upgraded with every passing day, it is definitely a good idea to know how it works and what goes inside the making of these screens. One of the major components in your touch and display panels is indium tin oxide or In2O3. This is a transparent material that is highly conductive.
Here is all you need to know about this interesting component and how it is important in the current scenario.
Composition and properties
Indium Tin Oxide or ITO mainly consists of indium, tin, and oxygen in varying proportions. It is often referred to as a ternary composition, as it holds three different chemicals. The major criterion to describe this substance is its oxygen content. Typically, it is seen as an oxygen-saturated variant, and the other one is an unsaturated type also known as oxygen-deficient ITO.
Appearance-wise, indium tin oxide is usually seen as a transparent substance existing in thin layers. In a few cases, it exists in a bulky form, where it looks yellowish to grey. In both cases, this mirror substance resembling a metal lies in the infrared region of the spectrum.
This is one of the highly practical conducting oxides currently in use. This is due to the levels of electrical conductivity and optical transparency it has to offer. Both of these factors add to the easy deposition of this component.
Common deposition methods used in the industries include:
- Physical vapor deposition
- Electron beam evaporation
- Sputter deposition
Based on the method used for its deposition, the uses of ITO tend to vary. Here is a specified account of the processes and their applications.
Physical vapor deposition
Also known as Physical Vapour Transport or PVT, this method is a type of vacuum deposition which is used to thinly coat substances like metals, glass, ceramics, and polymers. The characteristic feature of this process is that it allows the material to transition from a condensed phase to vapor, which is accomplished through processes like evaporation and sputtering.
Applications of PVD methods
Aesthetic applications
This is one of the leading methods being used by popular manufacturers in the field of consumer electronics. By altering the composition of the substance sued for coating and tampering with the time period in a controlled manner, the color and thickness of the layers can be customized. This allows them to create attractive colors on rather mundane metals and glass, adding to the general finish and product quality as a whole.
Electron-beam Physical Vapour Deposition
Also, known as EBPVD, this is a form of deposition where a target anode is struck by an electron beam from a charged tungsten filament. All this happens under the condition of a high vacuum, transforming the target atoms into their gaseous phase respectively. Following this, the vapor is precipitated into its solid form through cooling in the vacuum chamber by the anode material.
Applications
This process bears a higher deposition rate, owing to which it is used mainly for industrial entities like thermal coatings, wear-resistance protectant layers, and also electronic and optical films for thin-film solar applications.
Sputter deposition techniques
In sputtering methods, an ITO sputtering target sputters material onto the substrate. The atoms subject to sputtering possess a wide energy distribution. By altering the energy and the conditions under which the ions are sputtered, the end result may vary. These properties are made accessible by controlling the background gas pressure, which is a mostly inert gas. This is done by various methods like
- Ion beam sputtering
- Reactive sputtering
- Ion-assisted sputtering
- High-target-utilization sputtering
- High-power impulse magnetron sputtering
- Gas flow sputtering
Applications
The major application of sputter deposition is sputter coating, which is a deposition process used to cover the chosen object with a thin layer of conducting substance. In most cases, the conducting substance used is a metal or alloy. This conductive coating is crucial to prevent the specimen from getting charged with an electron beam or to increase the signal-to-noise ratio.
Sputtering techniques paired with an ITO target results in a deposition process that is quasi-reactive. This technique can also be used to alter the resistance held by the ITO film.
Other important uses
In a more general context, ITO is commonly used in
- Flat panel displays
- Supermarket freezer doors
- Flexible electroluminescent green tapes
- Coatings for liquid crystal, OLED, plasma displays, and touch panels
- Solar cells
- Organic light emitting diodes
- Optical coatings
- Gas sensors
- Electrowetting
- Sensor coating in camera
- Strain gauges
Conclusion
On an ending note, the growth of technological awareness and consumption of electronic gadgets has now made ITO a highly sought-after material in the industry. Apart from being commonly used as a thin coating form, it is currently being experimented with and tried for usage across different sections of production.
