by Indium gallium zinc oxide (IGZO) is an amorphous oxide semiconductor composed of indium, gallium, zinc, and oxygen metals. This promising material could revolutionize display technology by enabling thinner, lighter, and more energy-efficient displays. As demand grows for flexible devices like foldable smartphones and smart wearables, IGZO is emerging as a viable alternative to traditional amorphous silicon for next-generation displays.
Properties and Advantages of IGZO
IGZO has several properties that make it well-suited for displays in modern electronics. First, it is highly transparent in its amorphous form, meaning it can still transmit light effectively when used in display technology. It also has excellent field-effect mobility even as an amorphous semiconductor. This means devices can still operate quickly and smoothly without the need for crystals to form.
Perhaps most importantly, IGZO is compatible with low-temperature processing. Traditional amorphous silicon requires temperatures upwards of 600°C during fabrication, limiting potential substrates. IGZO can be deposited at room temperature and annealed at only 150-200°C. This low thermal budget means IGZO can be integrated into plastic, glass, and other flexible materials without damaging them. The ability to build displays on flexible plastic instead of rigid glass opens up huge potential for foldable and rollable designs.
IGZO is also extremely energy efficient compared to traditional amorphous silicon. Field-effect transistors built with IGZO switch on and off using 30-60% less power. This creates major power savings for battery life in portable devices as well as reduces heat output. IGZO’s superior uniformity over large areas also enables more consistent transistor performance across an entire display panel.
Applications in Flexible Displays
Given these characteristics, IGZO is primed to take the display industry by storm. It is already being commercialized in high-end LCD TVs and monitors from companies like Sharp and LG where its energy savings allow for thinner designs. However, its biggest impact may come through flexible and foldable displays.
Several smartphone and PC manufacturers have unveiled prototypes featuring IGZO-based screens that can bend, fold, or roll up without damage. For example, in 2016 Samsung unveiled the Galaxy Note 7 with an IGZO-based “Infinity Display” that extended almost edge-to-edge on the front of the device. This provided more viewing area while keeping the device footprint compact.
Looking ahead, IGZO will enable truly flexible smartphone designs that can fold in half or roll up like paper for easy portability. Concept designs by companies like TCL and Royole have demonstrated fully functional IGZO displays just a few millimeters thick that maintaining full responsiveness even when folded. Such designs could dramatically expand screen real estate without increasing device size in a user’s pocket or bag.
Smartwatches and Wearables
The wearable market is another major area primed for disruption by IGZO technology. Devices like smartwatches, fitness trackers, and head-up displays require displays that can conform to wrists, arms, glasses and other curved form factors comfortably. IGZO’s ability to integrate into plastic and flexible substrates will allow optical sensors, batteries and other components to wrap around users’ bodies seamlessly.
Several startups are already leveraging IGZO for next-gen wearables. For example, UK-based Plastic Logic has developed a “paper-like” electronic paper display technology using IGZO that is razor-thin, highly flexible and consumes very little power. Their novel design could enable truly wearable devices indistinguishable from ordinary wristbands. LG has also demonstrated a prototype IGZO smartwatch featuring a wrap-around curved screen just 0.1mm thick. Mass adoption of such hyper-flexible designs could transform what users expect from wearable technology.
Additional Applications
Aside from displays, IGZO also shows promise for several other applications due to its advantageous transistor characteristics:
Radio-frequency identification (RFID) tags: IGZO FETs provide efficient switching needed for digital data processing in low-power RFID and NFC chip applications. Their performance exceeds silicon at fractional size.
Printed/organic electronics: IGZO can be deposited at low temperatures compatible with printing processes using flexible plastic substrates. This enables innovative design possibilities like printed medical sensors, consumer product packaging with interactive displays and more.
Solid-state lighting: IGZO TFTs rival polysilicon in addressing flat and flexible LED/OLED panels used for lighting, signage and more. Higher mobility means greater design flexibility.
As technology marches toward the fully connected world of 5G, artificial intelligence and the internet of things, compatibility with flexible form factors will become increasingly important. IGZO semiconductor technology could serve as the enabling material to take displays, sensors and many other devices beyond the constraints of rigid silicon. By bringing the benefits of high performance, energy efficiency and flexible integration, IGZO promises to transform the user experience and user interface across industries. With continued development, it may soon become the new standard for displays in a post-mobile world.
