| AVS 65th International Symposium & Exhibition | |
| Thin Films Division | Thursday Sessions |
| Session TF+AS+EL+EM+NS+PS+SS-ThA |
| Session: | IoT Session: Thin Films for Flexible Electronics and IoT |
| Presenter: | Paul Poodt, Holst Centre / TNO and SALDtech B.V., Netherlands |
| Authors: | C. Frijters, Holst Centre / TNO, Netherlands I. Katsouras, Holst Centre / TNO, Netherlands A. Illiberi, Holst Centre / TNO, Netherlands G. Gelinck, Holst Centre / TNO, Netherlands P. Poodt, Holst Centre / TNO and SALDtech B.V., Netherlands |
| Correspondent: | Click to Email |
Atmospheric pressure Spatial ALD is able to deliver high deposition rates while maintaining the advantages of conventional ALD, such as low defect density, high conformality and thickness uniformity. An emerging application for Spatial ALD is flat panel (OLED) display manufacturing. Examples include oxide semiconductors and dielectric layers for use in thin-film transistors (TFT’s), and thin-film encapsulation for flexible OLED displays. As today’s displays are fabricated on glass plate sizes in the order of several square meters, a remaining challenge is the development of large-area Spatial ALD deposition technology that is able to combine high throughput with uniform performance across very large areas.
We are developing large area Spatial ALD technology, and as a first step between the lab and the display fab, we have installed a large area Spatial ALD sheet-to-sheet tool which can handle up to 400x325 mm2 sized substrates. With this tool we are able to deposit uniform films across a deposition width of 400 mm and thickness non-uniformities of ~ 1%. The whole tool is operated under an atmospheric pressure but inert N2 environment. The tool can be used to deposit a variety of materials using both thermal and plasma-enhanced Spatial ALD.
We will present about the fabrication and performance of 30 cm x 30 cm TFT backplanes with InZnOx (IZO) and InGaZnOx (IGZO) oxide semiconductors deposited by spatial ALD. The IZO and IGZO films were deposited by plasma enhanced Spatial ALD using co-injected In-, Ga- and Zn-precursors and an atmospheric pressure N2/O2 plasma. The deposition process has been optimized in terms of film composition and electrical properties on a lab-scale reactor before being translated to the large area spatial ALD rector. We will report on the yield and performance of the 30 cm x 30 cm TFT backplanes, including electrical properties such as the field effect mobility, Von and bias stress stability and compare it with state-of-the-art sputtered IGZO TFT’s. Finally, the challenges in up-scaling Spatial ALD to plate sizes of 1.5 m and beyond will be discussed.