Trap Assisted Conduction in High K Dielectric Capacitors on 4H-SiC


Article Preview

The characteristic of trap assisted conduction and interface states for a Pd/TiO2/SiO2/SiC structure has been investigated at temperatures up to 500 °C. Thermally oxidized Ti/SiO2 gate capacitors fabricated by dry oxidation in O2 were studied. The electrical measurements show the current conduction through this capacitor structure is controlled by a trap assisted conduction mechanism at low bias and the barrier height (φA) between the metal and the TiO2 was extracted. The current density in the dielectric stacks is also shown to be strongly temperature dependent. The results demonstrate that the formation of a charge dipole under the Pd contact is responsible for barrier height and not any changes in the behaviour of the TiO2 film itself, such as a change in concentration of trapping centres. The reported results indicate electron trapping property across the SiO2 layer is consistent with fitting experimental results to the trap assisted conduction model.



Materials Science Forum (Volumes 556-557)

Edited by:

N. Wright, C.M. Johnson, K. Vassilevski, I. Nikitina and A. Horsfall




M. H. Weng et al., "Trap Assisted Conduction in High K Dielectric Capacitors on 4H-SiC", Materials Science Forum, Vols. 556-557, pp. 679-682, 2007

Online since:

September 2007




[1] C.J. Anthony, A.J. Jones, and M.J. Uren: Mat. Sci. and Eng. Vol. B61-62 (1999), p.460.

[2] A. Lloyd Spetz, et al.: Thin Solid Films Vol. 299 (1997), p.183.

[3] J. P Xu, et al.: IEEE Electron Device Lett. Vol. 24 (2003), p.13.

[4] L.A. Lipkin and J.W. Palmour: IEEE Trans. Electron Devices Vol. 46 (1999), p.525.

[5] A. Lloyd Spetz et al.: Phys. Stat. Sol. (a) Vol. 185 (2001), p.15.

[6] H.S. Kim, S.A. Campbell and D.C. Gilmer: IEEE Elec. Dev. Lett. Vol. 18 (1997), p.465.

[7] L.H. Chong, et al, J. Phys.: Condens. Matter Vol. 18 (2006), p.645.

[8] M.H. Weng, R. Mahapatra, P. Tappin, B. Miao, S. Chattopadhyay, A.B. Horsfall, and N.G. Wright: EMRS Spring meeting, In press (2006).

[9] T.E. Rudenko et al.: Solid-State Electronics Vol. 49 (2005), p.545.

[10] C.K. Kim et al.: Sens. Actuators B Vol. 77 (2001), p.455.

[11] B.I. Shklovskii and A.L. Efros: in Electronic Properties of Doped Semiconductors, Springer-Verlag, (1984).

[12] P. Fiorenza et al.: Journal of Applied Physics Vol. 98 (2005), 044312.