| AVS 64th International Symposium & Exhibition | |
| Thin Films Division | Tuesday Sessions |
| Session TF-TuM |
| Session: | Advanced CVD and ALD Processing, ALD Manufacturing and Spatial-ALD |
| Presenter: | Fabien Piallat, KOBUS, France |
| Authors: | F. Piallat, KOBUS, France L. Bonnet, KOBUS, France J. Vitiello, KOBUS, France |
| Correspondent: | Click to Email |
A specific pulsed-CVD reactor was developed for the chemically enhanced deposition of materials. In this specific reactor, both reactant and precursor can be pulsed or sent continuously to the deposition chamber. Thus, many materials can be deposited by one of the three following methods, Atomic Layer Deposition (ALD), Chemical Vapor Deposition (CVD) or pulsed-CVD.
In this presentation, an investigation of Al2O3 deposition will be presented, with detailed process comparison for each of the three techniques in order to highlight the variability brought by the process on the material properties. Al2O3 deposition was done with TriMethylAluminium (TMA) precursor and O2 in-situ plasma.
Influence of the pulse length on the deposition rate shows a gap between the surface saturation growth mode of the ALD and the continuous growth of the CVD. Starting with pulse length in the order of seconds, in the case of the ALD mode, a reduction of the pulse length leads first to a reduction of the growth rate, because the precursor does not have enough time to adsorb at the sample surface to form a monolayer. Then, in a second time, for pulse time in the order of hundreds milliseconds, there is an increase of the growth rate, due to the change in the growth mode, from the surface saturation to the continuous growth. Further reduction of the pulse length, in the order of tens milliseconds, the growth can be assimilated to a CVD growth, with properties similar to the one of material obtained in continuous growth.
Additionally, extraction of the activation energy of the deposition reaction, using the Arrhenius law from deposition at temperature ranging from 100°C up to 450°C, will give some insight on the importance of the process on the favoring of the deposition reaction.
Finally, to address the photonic and MEMS applications, thick layers of Al2O3 will be deposited by the three methods and will be characterized by ellipsometry, Fourrier Transformed Infra-Red (FTIR), Raman measurement and X-ray Diffration (XRD). Pro and cons of each technique will be discussed based on these characterizations.