Deposition temperature dependence of material and Si surface passivation properties of O{sub 3}-based atomic layer deposited Al{sub 2}O{sub 3}-based films and stacks
- Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands and Hanwha Q CELLS GmbH, Sonnenallee 17-21, 06766 Bitterfeld-Wolfen (Germany)
- Hanwha Q CELLS GmbH, Sonnenallee 17-21, 06766 Bitterfeld-Wolfen (Germany)
- Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands)
The material composition and the Si surface passivation of aluminum oxide (Al{sub 2}O{sub 3}) films prepared by atomic layer deposition using Al(CH{sub 3}){sub 3} and O{sub 3} as precursors were investigated for deposition temperatures (T{sub Dep}) between 200 °C and 500 °C. The growth per cycle decreased with increasing deposition temperature due to a lower Al deposition rate. In contrast the material composition was hardly affected except for the hydrogen concentration, which decreased from [H] = 3 at. % at 200 °C to [H] < 0.5 at. % at 400 °C and 500 °C. The surface passivation performance was investigated after annealing at 300 °C–450 °C and also after firing steps in the typical temperature range of 800 °C–925 °C. A similar high level of the surface passivation performance, i.e., surface recombination velocity values <10 cm/s, was obtained after annealing and firing. Investigations of Al{sub 2}O{sub 3}/SiN{sub x} stacks complemented the work and revealed similar levels of surface passivation as single-layer Al{sub 2}O{sub 3} films, both for the chemical and field-effect passivation. The fixed charge density in the Al{sub 2}O{sub 3}/SiN{sub x} stacks, reflecting the field-effect passivation, was reduced by one order of magnitude from 3·10{sup 12} cm{sup −2} to 3·10{sup 11} cm{sup −2} when T{sub Dep} was increased from 300 °C to 500 °C. The level of the chemical passivation changed as well, but the total level of the surface passivation was hardly affected by the value of T{sub Dep}. When firing films prepared at of low T{sub Dep}, blistering of the films occurred and this strongly reduced the surface passivation. These results presented in this work demonstrate that a high level of surface passivation can be achieved for Al{sub 2}O{sub 3}-based films and stacks over a wide range of conditions when the combination of deposition temperature and annealing or firing temperature is carefully chosen.
- OSTI ID:
- 22258562
- Journal Information:
- Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films, Vol. 32, Issue 1; Other Information: (c) 2014 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0734-2101
- Country of Publication:
- United States
- Language:
- English
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