Abstract
The intrinsic point defects in a-SiO2 have recently received considerable attention. Careful use of paramagnetic resonance, coupled with annealing and optical studies, has led to unambiguous identification of three fundamental defects. These are the E′ center, the superoxide radical and the nonbridging oxygen hole center (NBOHC). Theoretical studies of the first two defects have led to greater understanding of experiment through inclusion of atomic relaxation. Two models exist for the NBOHC. One, by Skuja and Silin, invokes a Jahn-Teller splitting to explain 2 eV optical transitions. The other, by Griscom, is an extension of a model devised for alkali silicate glasses and involves pairs of oxygens, one of which is adjacent to a proton. Using MOPN, a semiempirical spin-unrestricted molecular orbital program, we have done molecular orbital studies of both NBOHC models. Our results support the Griscom model and not the Skuja-Silin model. These results, coupled with our earlier calculations on the E′ and superoxide defects, allow us to address defect formation and transformation processes in a logical way. In particular, these results are consistent with our speculations on the sequential creation of NBOHC, superoxide precursor, and superoxide radical by hole trapping.
This is a preview of subscription content, log in via an institution.
Buying options
Tax calculation will be finalised at checkout
Purchases are for personal use only
Learn about institutional subscriptionsPreview
Unable to display preview. Download preview PDF.
References
D. J. DiMaria, in The Physics of SiO 2 and its Interfaces, ed. S. T. Pantelides, Pergamon, New York, 160:references therein, (1978).
R. A. Weeks and C. M. Nelson, J. Am. Ceram. Soc. 43:399 (1960).
D. L. Griscom, Phys. Rev. B22:1729 (1980).
M. Stapelbroek, D. L. Griscom, E. J. Friebele and G. H. Sigel, Jr., J. Non-Cryst. Solids 32:313 (1979).
The water content of fused silica is measured in ppm OH. The dryest fused silica, suprasil Wl, contains 5–10 ppm OH, while suprasil 1 contains ~ 1200 ppm OH. Recent SIMS studies of thermal MOS oxides indicate there is at least 5–10 ppm OH in the oxide for even the dryest growing conditions. (R. Gale, F. J. Feigl, C. W. Magee, and D. R. Young, J. Appl. Phys. 54:6938 (1983)).
F. L. Galeener and M. F. Thorpe, Phys. Rev. B28:5802 (1983).
A. E. Geissberger and F. L. Galeener, Phys. Rev. B28:3266 (1983).
J. C. Phillips, in Solid State Physics, ed. F. Seitz and D. Turnbull, Academic Press, New York, 37:93 (1982).
As examples we cite references 3 and 4.
L. N. Skuja and A. R. Silin, Phys. Stat. Sol. (a) 70:43 (1982).
R. C. Bingham, M. J. S. Dewar, and D. H. Lo, J. Am. Chem. Soc. 97:1285 (1975).
P. Bischof, J. Am. Chem. Soc. 98:6844 (1976).
A. H. Edwards and W. B. Fowler, J. Phys. Chem. Sol. 46:841 (1985).
P. C. Taylor, J. F. Baugher and H. M. Kriz, Chem. Rev. 75:205 (1975).
F. J. Feigl, W. B. Fowler, and K. L. Yip, Sol. State. Comm. 14:225 (1974).
K. L. Yip and W. B. Fowler, Phys. Rev. B11:2327 (1975).
R. H. Silsbee, J. Appl. Phys. 32:1459 (1961).
D. L. Griscom, E. J. Friebele and G. H. Sigel, Jr., Sol. State Comm. 15:479 (1974).
D. L. Griscom, Nucl. Inst. and Methods Bl:481 (1984).
M. G. Jani, R. B. Bossoli, and L. E. Halliburton, Phys. Rev. B27:2285 (1983).
At this conference, we have heard about three spectroscopically different E′ centers in a-SiO2. In this chapter, we will only consider the E′ γ center.
H. A. Jahn and E. Teller, Proc. Roy. Soc. London A161:220 (1937).
F. S. Ham, Phys. Rev. B8:2926 (1973).
J. K. Rudra and W. B. Fowler, Bull. Am. Phys. Soc. 30:369 (1985).
A. H. Edwards and W. B. Fowler, Phys. Rev. B26:6649 (1982).
Recently, Jani, Bossoli and Halliburton have performed an extensive study on the formation mechanisms and the spin Hamiltonian parameters of the E1′ center in alpha quartz (Ref. 20). In this study they proposed a new model, based on an analysis of the angular dependence of the weak hyperfine lines. The two sets of lines are attributed to two of the next nearest neighbor silicon atoms, each bonded to one of the back-bonded oxygen atoms in the lower half of Fig, la. Further, the absence of a hyperfine signal from the third silicon atom on this side of the defect was attributed to a second oxygen vacancy. This is in stark contrast to the Feigl-Fowler-Yip model, wherein the two sets of weak hyperfine lines are attributed to the silicon atom in the upper half of Fig. la, and to another unspecified silicon atom. The recent calculations of Rudra and Fowler (Ref. 24) have rendered the double vacancy model extremely doubtful.
Using ENDOR, Jani et al. (Ref. 20) have recently determined that the strong hyperfine lines in alpha quartz are also due to interaction with a 29Si nucleus, rather than a proton.
A. V. Shendrick and D. M. Yudin, Phys. Stat. Sol. (b) 85:343 (1978).
G. Gobsch, H. Haberlandt, H. J. Weckner, and J. Reinhold, Phys. Stat. Solidi 90:309 (1978).
D. L. Griscom and E. J. Friebele, Phys. Rev. B24:4896 (1981).
E. J. Friebele, D. L. Griscom, M. Stapelbroek, and R. A. Weeks, Phys. Rev. Lett. 42:1346 (1979).
O. A. Ershov, D. A. Goganov, and A. P. Lukirskii, Sov. Phys. Solid State 7:1903 (1966).
D. L. Griscom, J. Non-Cryst. Solids 24:155 (1977).
K. L. Yip and W. B. Fowler, Phys. Rev. B10:1400 (1974).
J. A. Tossel, J. Phys. Chem. Sol. 34:307 (1973).
S. J. Louisnathan and G. V. Gibbs, Am. Mineral. 57:1614 (1972).
J. A. Tossel, J. Am. Chem. Soc. 97:4840 (1975).
G. A. D. Collins, D. W. Cruickshank, and A. Breeze, J. Chem. Faraday Trans. II 68:1189 (1972).
G. V. Gibbs, Amer. Mineral. 67:421 (1982).
J. M. Baker and P. T. Robinson, Sol. State Comm. 48:551 (1983).
D. L. Griscom, private communication.
G. Lucovsky, Philos. Mag. B39:513 (1979)
G. Lucovsky, Philos. Mag. B39:531 (1979)
G. Lucovsky, Philos. Mag. 41:457 (1980).
G. Lucovsky, J. Non-Cryst. Solids 35–36:825 (1980).
E. H. Poindexter, P. J. Caplan, R. L. Pfeffer, A. H. Edwards, and W. Muller-Warmuth, Bull. Am. Phys. Soc. 29:368 (1984).
B. I. Vikhrev, N. N. Gerasimenko, and G. P. Lebedev, Soviet Physics: Microelectronics 6:71 (1977).
K. L. Brower, P. M. Lenahan, and P. V. Dressendorfer, Appl. Phys. Lett. 41:251 (1982).
The heat of formation is defined in MINDO/3 as the difference between the total self consistent energy, and the sum of the isolated, single atom energies.
S. Urnes, Trans. Brit. Ceram. Soc. 60:85 (1961).
D. L. Griscom, M. Stapelbroek, and E. J. Friebele, J. Chem. Phys. 78:1638 (1983).
R. Pfeffer and D. L. Griscom, to be published.
This defect has been investigated previously, using a one-electron, tight-binding technique (E. P. O’Reilly and J. Robertson, Phys. Rev. B27:3780 (1983)). However, electron-electron interactions (for the negative state) and electron lattice interactions were not included.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 1986 Plenum Press, New York
About this chapter
Cite this chapter
Edwards, A.H., Fowler, W.B. (1986). Semiempirical Molecular Orbital Studies of Intrinsic Defects in a-SiO2 . In: Walrafen, G.E., Revesz, A.G. (eds) Structure and Bonding in Noncrystalline Solids. Springer, Boston, MA. https://doi.org/10.1007/978-1-4615-9477-2_8
Download citation
DOI: https://doi.org/10.1007/978-1-4615-9477-2_8
Publisher Name: Springer, Boston, MA
Print ISBN: 978-1-4615-9479-6
Online ISBN: 978-1-4615-9477-2
eBook Packages: Springer Book Archive