Total

1
Border Traps and Dipoles in SiO2
Dan Fleetwood Vanderbilt University (615)
322-2498 dan.fleetwood_at_vanderbilt.edu
Acknowledgments This work was supported in part
by the Defense Threat Reduction Agency and
AFOSR/MURI.
2
Outline

• Border Traps
• Near-interfacial oxide traps that exchange charge
  with Si
• D. M. Fleetwood, IEEE Trans. Nucl. Sci. 39, 269
  (1992)
• Stable Dipoles
• The Si-H multiple roles?

3
Hole Capture, and Annealing or Compensation
A. J. Lelis, T. R. Oldham, H. E. Boesch, Jr., and
F. B. McLean, IEEE Trans. Nucl. Sci., 36, 1808
(1989).
4
Dipoles that Switch
J. F. Conley, Jr., P. M. Lenahan, A. J. Lelis,
and T. R. Oldham, IEEE Trans. Nucl. Sci., 42,
1744 (1995).
Also contribute to C-V hysteresis D. M.
Fleetwood and N. S. Saks, J. Appl. Phys., 79,
1583 (1996). W. L. Warren et al., IEEE TNS 41,
1817 (1994)
5
Oxide and Border Traps
No dipole
Dipole that switches
Dipole in highly stretched Configuration
(switchable)
Z. Y. Lu, C. J. Nicklaw, D. M. Fleetwood, R. D.
Schrimpf, and S. T. Pantelides, Phys. Rev. Lett.
89, 285505-1 to 285505-4 (2002). D. M. Fleetwood,
H. D. Xiong, Z. Y. Lu, C. J. Nicklaw, J. A.
Felix, R. D. Schrimpf, and S. T. Pantelides, IEEE
Trans. Nucl. Sci. 49, 2674 (2002). C. J. Nicklaw,
Z. Y. Lu, D. M. Fleetwood, R. D. Schrimpf, and S.
T. Pantelides, IEEE Trans. Nucl. Sci. 49,
2667-2673 (2002).
6
Dipoles that Dont Switch!
45 nm oxides 2 Mrad (SiO2) 10 V 15 min 12 V
anneal (isochronal)
D. M. Fleetwood, P. S. Winokur, O. Flament, and
J. L. Leray, Appl. Phys. Lett., 74, 2969 (1999).
7
Si-H Dipole (or Half Dipole)
1.6e-
Si-H plus positive charge shows dipolar nature
Similar association of Si-H with surface
dipoles e.g., M. Houssa et al., Appl. Phys.
Lett., 81, 709 (2002) W. Mönch, J. Vac.
Sci. Technol. B, 14, 2985 (1996).
S. N. Rashkeev, D. M. Fleetwood, R. D. Schrimpf,
and S. T. Pantelides, IEEE Trans. Nucl. Sci. 48,
2086-2092 (2001). S. N. Rashkeev, D. M.
Fleetwood, R. D. Schrimpf, and S. T. Pantelides,
Phys. Rev. Lett. 87, 165506-1 to 165506-4 (2001).
8
Possible Support from Nitridation Studies
From TSC
D. M. Fleetwood and N. S. Saks, J. Appl. Phys.,
79, 1583 (1996).
9
Conclusion and Future Work

• Trapped positive charge can enhance negative
  charge on Si-H
• Perhaps helps reduce net positive oxide-trap
  charge
• Other effects unknown
• Interesting topic for future experimental and
  theoretical investigation
• Energy levels
• Implications for thin oxide reliability and high
  K dielectrics
• Relevance to negative bias temperature
  instability?