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Optimization of 75°C amorphous silicon nitride for TFTs on plastics

Published online by Cambridge University Press:  15 February 2011

Christian McArthur
Affiliation:
Electrical and Computer Engineering Department University of Waterloo Waterloo, Ontario, N2L 3G1, Canada
Mark Meitine
Affiliation:
Electrical and Computer Engineering Department University of Waterloo Waterloo, Ontario, N2L 3G1, Canada
Andrei Sazonov
Affiliation:
Electrical and Computer Engineering Department University of Waterloo Waterloo, Ontario, N2L 3G1, Canada
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Abstract

Amorphous silicon nitride (a-SiNx) is widely used as the gate dielectric and passivation layer in a-Si:H based electronics. For devices on plastic substrates deposited at low temperature, the a-SiNx quality seems to determine the device performance. This paper investigates the effects of hydrogen dilution, helium dilution, ammonia-silane gas flow ratio, and RF power on the properties of PECVD silicon nitrides deposited in large-area parallel-plate reactors at substrate temperatures of 75°C. The chemical composition and bonding of the SiNx:H films was studied using FTIR spectroscopy. The physical properties were investigated, and the density, growth rate, and compressive stress of the films were determined. The electrical properties such as leakage current, breakdown, stability, trap density, and dielectric constant of the films were characterized by I-V and C-V measurements of metal-insulator semiconductor (MIS) structures. Analysis of Variance (ANOVA) was performed on the results, and the deposition conditions for the optimal film properties were determined. The optimum film had SiNx:H stoichiometry of x=1.56 with hydrogen concentrations of 17 at.%, and exhibited compressive stress of -220 MPa. The film displayed good stability under electrical stress with ohmic leakage of Rleak ∼1016 Ωcm. Strong relationships between the film properties and deposition conditions were observed, and are discussed within the paper. A-Si:H bottom gate TFTs were fabricated using the optimized nitrides for gate dielectrics and passivation layers, and the influence of a-SiNx on TFT performance is discussed.

Type
Research Article
Copyright
Copyright © Materials Research Society 2003

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References

[1] Garcia, S., Martil, I., Diaz, G. Gonzalez, Fernandez, M., Semicond. Sci. Technol. 12, 1650 (1997).Google Scholar
[2] Roy, R., A Primer on the Taguchi Method, (New York: Van Nostrand Reinhold, 1990).Google Scholar
[3] Baets, J. De, Calster, A. Van, Capon, J., Rycke, I. De, Smet, H. De, Doutreloigne, J., Vanfleteren, J., Proceedings of the first symposium on thin film transistor technologies, 192 (1992).Google Scholar
[4] Sazonov, A., Stryahilev, D., Nathan, A., Bogomolova, L., J. Non-Cryst. Solids 299-302, 1360 (2002).Google Scholar
[5] Terry, F.L., Wyatt, P.W., Naiman, M.L., Mathur, B.P., Kirk, C.T., J.Appl. Phys. 57, 2036 (1985).Google Scholar
[6] Lucovsky, G., Phillips, J.C., J. Non-Cryst. Solids 227-230, 1221 (1998).Google Scholar
[7] Klein, T.M., Anderson, T.M., Chowdhury, A.I., Parsons, G.N., J. Vac. Sci. Technol. A 17, 108 (1999).Google Scholar
[8] Kobayashi, I., Ogawa, T., Hotta, S., Jpn. J. Appl. Phys. 31, 336 (1992).Google Scholar
[9] Yang, C.S., Smith, L.L., Arthur, C.B., Parsons, G.N., J. Vac. Sci. Technol. B 18, 683 (2000).Google Scholar