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High Mobility ZnO thin film transistors using the novel deposition of high-k dielectrics

Published online by Cambridge University Press:  05 April 2011

D. K. Ngwashi
Affiliation:
Emerging Technologies Research Centre, De Montfort University Leicester LE1 9BH, UK
R. B. M. Cross
Affiliation:
Emerging Technologies Research Centre, De Montfort University Leicester LE1 9BH, UK
S. Paul
Affiliation:
Emerging Technologies Research Centre, De Montfort University Leicester LE1 9BH, UK
Andrian P. Milanov
Affiliation:
Inorganic Materials Chemistry Group, Inorganic Chemistry II, Ruhr-University Bochum, 44801 Bochum, Germany
Anjana Devi
Affiliation:
Inorganic Materials Chemistry Group, Inorganic Chemistry II, Ruhr-University Bochum, 44801 Bochum, Germany
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Abstract

In order to investigate the performance of ZnO-based thin film transistors (ZnO-TFTs), we fabricate devices using amorphous hafnium dioxide (HfO2) high-k dielectrics. Sputtered ZnO was used as the active channel layer, and aluminium source/drain electrodes were deposited by thermal evaporation, and the HfO2 high-k dielectrics are deposited by metal-organic chemical vapour deposition (MOCVD). The ZnO-TFTs with high-k HfO2 gate insulators exhibit good performance metrics and effective channel mobility which is appreciably higher in comparison to SiO2-based ZnO TFTs fabricated under similar conditions. The average channel mobility, turn-on voltage, on-off current ratio and subthreshold swing of the high-k TFTs are 31.2 cm2V-1s-1, -4.7 V, ~103, and 2.4 V/dec respectively. We compared the characteristics of a typical device consisting of HfO2 to those of a device consisting of thermally grown SiO2 to examine their potential for use as high-k dielectrics in future TFT devices.

Type
Research Article
Copyright
Copyright © Materials Research Society 2011

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References

REFERENCES

1. Moore, A.R., Electron and hole drift mobility in amorphous silicon . Applied Physics Letters, 1976. 31(11): p. 761–4.Google Scholar
2. Gleskova, H. and Wagner, S., Electron mobility in amorphous silicon thin-film transistors under compressive strain . Applied Physics Letters, 2001. 79(20): p. 3347–9.Google Scholar
3. Yi, T., et al. , Study of light induced instability in intrinsic hydrogenated amorphous silicon films by the photomixing technique . Applied Physics Letters, 1996. 68(5): p. 640–2.Google Scholar
4. Voronkov, E.N. Current instability in a-Si:H solar cells after their exposure to light. 2001. Russia: MAIK Nauka.Google Scholar
5. Ngwashi, D., Cross, R.B., and Paul, S.. Electrically Air-stable ZnO Thin Film Produced by Reactive RF Magnetron Sputtering for Thin Film Transistors Applications . in Mat. Res. Soc. 2009. 1201: p. 153–158Google Scholar
6. Hirao, T., et al. , Bottom-gate zinc oxide thin-film transistors (ZnO TFTs) for AM-LCDs . IEEE Transactions on Electron Devices, 2008. 55(11): p. 3136–3142.Google Scholar
7. Hirao, T., et al. Distinguished paper: High mobility top-gate Zinc Oxide Thin-Film Transistors (ZnO-TFTs) for active-matrix liquid crystal displays. 2006. San Francisco, CA, United states: Society for Information Display.Google Scholar
8. Carcia, P.F., et al. , Transparent ZnO thin-film transistor fabricated by rf magnetron sputtering . Applied Physics Letters, 2003. 82(7): p. 1117–1119.Google Scholar
9. Nishii, J., et al. , High mobility thin film transistors with transparent ZnO channels . Japanese Journal of Applied Physics, Part 2 (Letters), 2003. 42(4A): p. 347–9.Google Scholar
10. Hossain, F.M., et al. , Modeling and simulation of polycrystalline ZnO thin-film transistors . Journal of Applied Physics, 2003. 94(12): p. 7768–77.Google Scholar
11. Milanov, A.P., et al. , Lanthanide oxide thin films by metalorganic chemical vapor deposition employing volatile guanidinate precursors . Chemistry of Materials, 2009. 21(22): p. 5443–5455.Google Scholar
12. Remashan, K., et al. , Impact of hydrogenation of ZnO TFTs by plasma-deposited silicon nitride gate dielectric . IEEE Transactions on Electron Devices, 2008. 55(10): p. 2736–43.Google Scholar
13. Taur, Y. and Ning, T.H., Fundamentals of Modern VLSI Devices. 1998: Cambridge University Press. p. 128.Google Scholar
14. Park, Y.R., Kim, J., and Kim, Y.S., Effect of hydrogen doping in ZnO thin films by pulsed DC magnetron sputtering . Applied Surface Science, 2009. 255(22): p. 9010–9014.Google Scholar
15. Shi, G.A., et al. , “Hidden hydrogen” in as-grown ZnO . Applied Physics Letters, 2004. 85(23): p. 5601–3.Google Scholar