| AVS 58th Annual International Symposium and Exhibition | |
| Thin Film Division | Monday Sessions |
| Session TF-MoA |
| Session: | Emerging ALD Applications |
| Presenter: | Matti Putkonen, Beneq Oy, Finland |
| Correspondent: | Click to Email |
Atomic Layer Deposition (ALD) has been successfully applied to antireflection, buffer and passivation layers for PV as well as moisture barriers for OLED packaging. In these applications ALD offers superior performance compared to the corresponding layers deposited with other methods. Outside IC manufacturing ALD has largely been confined to laboratories so far due to non-availability of larger scale, high throughput ALD systems. For example, ALD is widely seen as the desired manufacturing technology for producing high quality functional layers into solar cells: e.g. buffer layers into CIGS and surface passivation into both p-type and n-type c-Si solar cells, but ALD commonly considered too slow for high throughput manufacturing.
In this presentation we introduce commercial high capacity ALD tools for PV and OLED diffusion barrier applications as well as discuss more about the requirements for high throughput industrial ALD tools. Conventional ALD deposition parameters and characteristics, such as stability of precursor temperatures even with extremely high precursor doses and optimising the flow path are needed before strict coating requirements can be fulfilled.
The TFS 1200 deposition system is designed to improve efficiency of CuInGaSe2 (CIGS) type thin film PV cells using Zn(O,S)) buffer layer. It has throughput in inline and off-line configurations of 12 and 24 modules/hour, respectively. (substrate size 120 x 120 cm2, 20 nm Zn(O,S)) We have obtained thin film thickness uniformity of ± 3 % with the cycle time of 2.0 s. With 60 x 120 cm2 substrate size these numbers will be doubled to 24-48 modules/hour. These values fulfill the throughput requirements of CIGS production lines (20-60 modules/h). Even higher throughputs can be obtained using batch type tools for CIGS buffer layers.
TFS NX 300 is a fully automated cassette to cassette ALD manufacturing system for Al2O3 surface passivation. It consists of 4 processing tubes each with the capacity for a 500 wafer batch. For this application we have modified thermal ALD-process for Al2O3 which has a higher growth rate than the conventional thermal (TMA/H2O) ALD process and the film quality is equal to plasma assisted ALD film quality giving throughput of >3000 wafers/h.
The Beneq TFS 600 is a vacuum-line integrated ALD system for OLED moisture barrier coating. Reaction chamber is designed for batch processing up to 35 substrates measuring 500 mm x 400 mm. For this application we have been developing low-cost multilayer barrier structure giving WVTR <10-6 g/m2/d.