| AVS 60th International Symposium and Exhibition | |
| Thin Film | Tuesday Sessions |
| Session TF-TuA |
| Session: | High Throughput ALD |
| Presenter: | M. Smets, Holst Centre / TNO, Netherlands |
| Authors: | M. Smets, Holst Centre / TNO, Netherlands F. van den Bruele, Holst Centre / TNO, Netherlands P. Poodt, Holst Centre / TNO, Netherlands |
| Correspondent: | Click to Email |
Spatial-ALD is emerging as an industrially scalable deposition technology at atmospheric pressure which combines the advantages of temporal ALD, i.e. excellent control of film composition and uniformity on large area substrates, with high growth rates (~ nm/s). Whereas in conventional ALD, precursors are dosed in a time-separated mode using a purge or pump step, in spatial ALD, precursors are dosed simultaneously and continuously at different physical locations. As a result, deposition rates exceeding 1 nm/s have been reported for spatial atmospheric ALD of Al2O3. This has led to the development of high-throughput, industrial scale ALD tools for surface passivation of crystalline silicon solar cells as well as roll-to-roll spatial ALD concepts for applications in flexible electronics.
Atomic layer deposition is mostly used to deposit conformal inorganic films. Organic- and hybrid organic-inorganic films can be also be deposited by ALD, which is then referred to as Molecular Layer Deposition (MLD). For example, by combining metal precursors and various organic alcohols, metal alkoxide films or “metalcones” can be obtained. By varying both the metal precursor and organic precursor, the optical, mechanical, electrical and chemical properties of the film can be tuned.
This presents opportunities for applications such as catalysis, light management, and many others.
We have combined both techniques to do Spatial MLD to deposit several metalcones by combining various metal- and organic precursors. E.g. alucone layers have been deposited using TMA with ethylene glycol, with a growth per cycle (GPC) of about 0.5 nm/cycle and a refractive index of 1.50 at 630 nm. The GPC decreases with increasing deposition temperature and there appears to be an optimum for the ethylene glycol concentration. The optical, chemical and mechanical properties of the films have been investigated by means of e.g. ellipsometry, ATR-FTIR and nano-indentation.
These results show that Spatial MLD is a promising technique to deposit a wide range of new, functional materials at high deposition rates.