ALD

This is a sponsored post by Ergis Group

In 2020, Poland-based Ergis Group launched the noDiffusion film platform, a high-barrier film that offers high level of optical transmittance and low level of light scattering, and the ability to contain transparent conductive electrodes. The new technologies adopted in the production of the barrier films offer a combination of high performance and competitive pricing.

Ergis has been busy since 2020, scaling up its production capabilities, and progressing towards production in a roll-to-roll configuration (rather than the batch system it used before). Ergis is using two different technologies - ALD and sputtering to deposit the barrier and the conductive electrodes.

Merck introduces new OLED encapsulation materials that the company says offer superior flexibility, higher reliability, and longer lifetime for flexible devices compared to existing solutions. 

Merck says that its new low-temperature ALD silicon materials offer highly improved barrier characteristics - 100 times more effective than current solutions. And they can be deposited in thin layers - 20 times thinner than existing solutions. Merck introduced low-temperature ALD silicon materials in 2022 for automotive OLED, and the company expects that the new materials will be used for the encapsulation of flexible IT OLED displays (laptops, tablets and monitors).

Researchers from the Holst Center has applied spatial atomic layer deposition (sALD) to create both the semiconductor and dielectric layer in a thin-film transistor (TFT) Oxide-TFT (IGZO) display backplane - for the first time ever.

The researchers created a 200 PPI QVGA OLED display prototype on a thin PEN foil. This shows how TFTs can be produced in a low temperature process (below 200 degrees Celsius) using sALD on a cheap transparent plastic foil. The TFTs achieved a mobility of 8 cm²/V2 with channel lengths down to 1 um.

The Netherlands based SALDtech, established in 2018 as a spinoff from the TNO institute, announced that it closed its 2^nd financing round led by Innovation Industries and BOM, Brabant Development agency.

SALDtech developed deposition tools based on the Holst Centre's Spatial Atomic Layer Deposition that can be used to produce large area ultra-thin layers with world class performance. SALDtech says it will used the investment to develop and build flexible OLED production equipment.

Researchers from the Korea Advanced Institute of Science and Technology (KAIST) developed a self-powered wearable and washable OLED display device. The whole device is fabricated on textiles and the efficient OLED devices are driven by polymer solar modules.

Both the OLED device and the polymer solar panels are sensitive to moisture and oxygen, and regular OLED encapsulation will not protect such a device when washed. The researches designed a new washable encapsulation barrier using both ALD and spin coating. The device is flexible (curvature radius of 3 mm) and survived 20 washing cycles of 10 minutes each with little change in performance.

Graphene is the world's most impermeable material, and as the material is also transparent, flexible and ultra-thin it makes sense to adopt graphene as an encapsulation layer for next-gen OLED displays. A UK project led by Cambridge University researchers have set out in 2015 to develop such a solution, and the researchers now report that they have demonstrated a viable graphene solution comparable to existing commercial OLED encapsulation technologies.

In its pure form, graphene is permeable to all gases, but real life materials are never entirely pure and defects and holes harm the material's permeability. The new research used ALD and CVD to create large-area high-quality single-layer graphene sheets which were stacked to create a multi-layer coating. The researchers say that a ~10 nm barrier layer that includes 3-4 layers of graphene (with AlOx in between) is an effective solution for OLED displays. The 10 nm layer maintains a high optical transparency (>90 %) and high flexibility.

UBI Research says that as OLED makers are diverting all efforts into flexible OLED production, thin film encapsulation (TFE) is gaining in popularity. Between 2017 and 2021, TFE will be applied to about 70% of all OLED panels in production. The OLED encapsulation equipment market will generate $11 billion in sales.

TFE encapsulation started out as a complex technology that required 11 layers and was slow and expensive. Recent advances allowed OLED makers to reduce the number of layers to just 3 and increase productivity and yields and so lower the production costs. Some film OLED makers opted for hybrid encapsulation (which uses a barrier film) but TFE seems to have become the technology of choice.

Researchers from the Holst Centre developed a new process to deposit semiconductor layers with better performance and high throughput than PVD-based process. the new process is based on scalable, atmospheric-pressure process spatial-ALD.

The Holst Centre used sALD to deposit IGZO backplanes that achieved charge carrier mobilities of 30 to 45 cm²/Vs. The researchers say that similar backplanes deposited with PVD (supttering) achieve about 10 cm²/Vs. The sALD layers also exhibited low off current, switch-on voltages around 0 V and excellent bias stress stability.