Holst Center researchers use sALD to create IGZO OLED display backplanes on PEN foils

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.

Holst sALD QVGA OLED prototype photo

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.

SALDtech announces its 2nd investment round, to develop flexible OLED deposition tools

SALDtech logoThe Netherlands based SALDtech, established in 2018 as a spinoff from the TNO institute, announced that it closed its 2nd 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.

KAIST researchers develop a washable wearable solar-powered OLED device

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.

Washable and wearable PSC and OLED device (KAIST)

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-based barrier demonstrated as a possible solution for flexible OLED encapsulation

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.

Graphene encapsulation research, CPI 2017

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 sees PECVD as the in-organic TFE equipment of choice for flexible OLED production

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.

PECVD oled encapsulation market share (UBI, 2017-2021)

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.

Encapsulix to supply ALD-TFE equipment to a leading Asian AMOLED producer

Encapsulix logoALD equipment maker Encapsulix announced that a leading Asian AMOLED manufacturer has chosen its ALD-TFE deposition systems, to be used as flexible AMOLED encapsulation. The first tool is already under construction and will start operating in the spring of 2017.

Encapsulix says that the order was awarded following an extensive evaluation of available ALD platforms, and this confirms the technological superiority and leading cost-of-ownership of the company's ALD-TFE equipment.

The Holst Center developed a Spatial-ALD TFT deposition process

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.

Display transistors deposited by sALD image

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.

Researchers develop a cheap and efficient MgO-based OLED encapsulation layer

Researchers from South China University of Technology (SCUT) demonstrated a new MgO-based OLED encapsulation layer. The researchers say that MgO provides an efficient barrier at a low cost, and can be deposited in low temperatures.

MgO OLED encapsulation tests (SCUT 2016)

The researchers say that this is the first time that MgO is used for OLED encapsulation, but this material has a number of advantages - a low refractive index, a wide bandgap, high dielectric constant, high chemical stability and the lack of UV irradiation treatment requirements.

Veeco significantly reduces its ALD investments

In September 2013, Veeco acquired Synos Technology for $185 million for the company's FAST-ALD flexible OLED encapsulation technology. Veeco did received a purchase order from SDC for a first-generation FAST-ALD prototype system, but the significant orders Veeco hopes to achieve never materialized.

In early 2015 Veeco announced that they do not see near-term revenue coming from this sector. Yesterday Veeco decided to significantly reduce future investments in its ALD technology development. Veeco says that some "competitive technologies" solved the display makers problems and it now sees ALD business pushed back two or three years.

Both Samsung and LG to switch to ALD for in-organic TFE?

A few days ago we reported that Kateeva says it has taken a "commanding lead" in the OLED thin film encapsulation (TFE) market with its ink-jet based systems. Kateeva's ink-jet printers are used to deposit organic materials, but the full TFE stack also contains in-organic materials.

Currently both LG and Samsung producers are using PECVD to deposit the in-organic materials, but according to a report from ETNEws, both Korean display makers are thinking about switching to ALD. Several companies, including Jusung Engineering, WONIK IPS, AP Systems and TES has ALD-based encapsulation deposition systems ready to be used in display production. Both LG and Samsung have finished with R&D work on ALD technology and are ready to introduce commercial systems into their production lines.

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