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Dependence of Reliability of Ultrathin Mos Gate Oxides on the Fermi Level Positions at Gate and Substrate

Published online by Cambridge University Press:  10 February 2011

Tien-Chun Yang ,
Navakanta Bhat  and
Krishna C. Saraswat
Tien-Chun Yang
Affiliation:
Department of Electrical Engineering, Stanford University, Stanford, CA 94305
Navakanta Bhat
Affiliation:
Department of Electrical Engineering, Stanford University, Stanford, CA 94305
Krishna C. Saraswat
Affiliation:
Department of Electrical Engineering, Stanford University, Stanford, CA 94305
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Abstract

We demonstrate that the reliability of ultrathin (< 10 nm) gate oxide in MOS devices depends on the Fermi level position at the gate, and not on the position at the substrate for constant current gate injection (Vg-). The oxide breakdown strength (Qbd) is less for p+ poly-Si gate than for n+ poly-Si gate, but, it is independent of the substrate doping type. The degradation of oxides is closely related to the electric field across the gate oxide, which is influenced by the cathode Fermi level. P+ poly-Si gate has higher barrier height for tunneled electrons, therefore, the cathode electric field must be higher to give the same injection current density. A higher electric field gives more high energy electrons at the anode, and therefore the damage is more at the substrate interface. Different substrate types cause no effect on the oxide electric field, and as a result, they do not influence the degradation.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 473: Symposium J – Materials Reliability in Microelectronics VII , 1997 , 123
Copyright
Copyright © Materials Research Society 1997

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References

REFERENCES

1. Degraeve, R., Groeseneken, G., Bellens, R., Depas, M., and Maes, H.E., “A consistent model for the thickness dependence of intrinsic breakdown in ultra-thin oxides', IEDM, pp. 863–866, 1995.Google Scholar
2. Han, L. K., Bhat, M., Wristers, D., Fulford, J., and Kwong, D. L., “Polarity dependence of dielectric breakdown in scaled SiO2 ”, IEDM, pp. 617–620, 1994.Google Scholar
3. Gong, Sheng S., Burnham, Marie E., David Theodore, N., and Schroder, Dieter K., “Evaluation of Qbd for electrons tunneling from the Si/SiO2 interface compared to electron tunneling from the poly-Si/SiO2 interface”, IEEE, TED, Vol. 40, No.7, pp. 1251–1257, July 1993.Google Scholar
4. Han, L. K., Bhat, M., Wristers, D., Wang, H. H., and Kwong, D. L., “Recent developments in ultra thin oxynitride gate dielectrics”, Microelectronic Engineering, 28, pp. 89–96, 1995.Google Scholar
5. Yoneda, Kenji, Fukuzaki, Yoshiki, Satoh, Kazuo, Hata, Yoshifumi, Todokoro, Yoshihiro, and Inoue, Morio, “Reliability degradation mechanism of ultrathin tunneling oxide by postannealing”, J. Electrochem. Soc., Vol. 138, No. 7, pp. 2090–2095, July 1991.Google Scholar
6. DiMaria, D. J., “Explanation for the polarity dependence of breakdown in ultrathin silicon dioxide films”, Applied Physics Letters, Vol. 68, No. 20, pp. 3004–3006, 1996.Google Scholar
7. Dumin, David J., Mopuri, Sai K., Vanchinathan, S., Scott, R.S., Subramoniam, R., and Lewis, Terrill G., “High field related thin oxide wearout and breakdown”, IEEE, TED, Vol. 42, No. 4, pp. 760–772, April 1995.Google Scholar
8. Arnold, D., Cartier, E., DiMaria, D. J., “Theory of high-field electron transport and impact ionization in silicon dioxide”, Physical Review B, vol.49, pp. 10278–10297, 1994.Google Scholar
9. DiMaria, D. J., Cartier, E., Arnold, D., “Impact ionization, trap creation, degradation, and breakdown in silicon dioxide films on silicon”, J. Appl Phys., 73(7), pp. 3367–3384, 1 April 1993.Google Scholar
10. Apte, Pushkar P., Kubota, Taishi and Saraswat, Krishna C., “Constant current stress breakdown in ultrathin Si02 films”, J. Electrochem. Soc., Vol. 140, No. 3, pp. 770–773, March 1993.Google Scholar
11. Schuegraf, Klaus F. and Hu, Chenming, “Hole injection SiO2 breakdown model for very low voltage lifetime extrapolation”, IEEE, TED, Vol. 41, No. 5, pp. 761–767, May 1994.Google Scholar