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Peculiar Doping Behavior of Si:Be.

Published online by Cambridge University Press:  26 February 2011

Eugen Tarnow
Affiliation:
Electronic Materials Laboratory, Xerox Palo Alto Research Center, 3333 Coyote Hill Road, Palo Alto, California 94304
S.B. Zhang
Affiliation:
Electronic Materials Laboratory, Xerox Palo Alto Research Center, 3333 Coyote Hill Road, Palo Alto, California 94304
K.J. Chang
Affiliation:
Department of Physics, Korea Advanced Institute of Science & Technology, Seoul, South Korea
D.J. Chadi
Affiliation:
Electronic Materials Laboratory, Xerox Palo Alto Research Center, 3333 Coyote Hill Road, Palo Alto, California 94304
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Abstract

The total energies and structures of a number of Be-induced defects in Si are investigated using ab-initio local density calculations. Our primary results are: 1) The geometry of the isoelectronic center is found to correspond to a [111] substitutionalinterstitial pair (SIP); 2) The low energy defect spectrum includes large Be complexes containing at least one substitutional atom; and 3) Simple bonding rules exist for the stability of the different types of bonds in the material. Thus the Si-Be bond is found to be stable for all defect configurations while the Be-Be bond is metastable.

Type
Research Article
Copyright
Copyright © Materials Research Society 1991

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References

REFERENCES

1. This measurement is attributed to Baker, John E. in reference 2.Google Scholar
2. Crouch, Roger K., Robertson, James B. and Glimer, T.E. Jr, Physical Review B, 5, 3111 (1971).CrossRefGoogle Scholar
3. Labrie, D., Timusk, T. and Thewalt, M.L., Phys. Rev. Lett. 52, 81 (1984).Google Scholar
4. Henry, M.O., Lightowlers, E.C., Killoran, N., Dunstan, D.J. and Cavenett, B.C., J. Phys. C: Solid State Physics, 14, L255 (1981).Google Scholar
5. Thewalt, M.L.W., Watkins, S.P., Ziemelis, U.O., Lightowlers, E.C. and Henry, M.O., Solid State Comm. 44, 573 (1982).Google Scholar
6. Killoran, N., Dunstan, D.J., Henry, M.O., Lightowlers, E.C. and Cavenett, B.C., J.Phys C: Solid State Phys, 15, 6067 (1982).Google Scholar
7. Henry, M.O., Moloney, Keith A., Treacy, J., Mulligan, F.J. and Lightowlers, E.C., J. Phys. C: Solid State Phys. 17, 6245 (1984).Google Scholar
8. Davies, Gordon and Henry, Martin, private communication.Google Scholar
9. Robertson, J.B. and Franks, R.K., Solid State Communications, 6, 825 (1968).Google Scholar
10. Kleverman, M. and Grimmeiss, H.G., Semicond. Sci. Technol. 1, 45 (1986).Google Scholar
11. Froyen, Sverre and Zunger, Alex, Phys. Rev. B 34, 7451 (1986).Google Scholar
12. Tarnow, Eugen, Zhang, S.B., Chang, K.J. and Chadi, D.J., Phys. Rev. B, to be published.Google Scholar
13. The formation energies are referenced to c-Si and metallic Be. In particular, the energy we quote for n-atom defects is the energy for n Be atoms to convert from Be metal to the specific configuration with any affected Si atoms going to a Si surface:Eform = Eform[SipBen] - pEform[c-Si] - nEform[Bemetal]Google Scholar
14. Davies, Gordon, J. Phys. C. 17, 6331 (1984).Google Scholar
15. The local mode frequencies for the isolated defects were obtained by assuming that the surrounding Si atoms do not move appreciably. This is justifyable since the Be atom is lighter than the Si atom by a factor of 3. The Be atoms then moved in a tetrahedrally symmetric potential and the frequencies reported are associated with the lowest eigenmode. We performed a test calculation for the substitutional defect allowing one of the Si atoms to move. We found that this changed the local mode frequency by 20 cm-1.Google Scholar
16. Again we approximated the surrounding lattice to be stationary. This should be a good approximation for the antisymmetric state (the effective mass is low), but worse for the symmetric state which has a high effective mass.Google Scholar
17. These estimates were calculated as follows: The upper bound of 0.8 eV was calculated assuming that the atomic coordinates in the configurations in between the local minima were simple linear interpolations. Thus the Si atoms were frozen and the Be atom was not allowed its most favorable path. Then we recalculated the energy barrier by allowing full relaxations of all the surrounding Si atoms. This “adiabatic” energy was found to be 0.4 eV and is too low, because the movement of the Be atom is not a fully adiabatic process.Google Scholar
18. van Kooten, J.J., Weller, G.A., and Ammerlaan, C.A.J., Phys. Rev. B 30, 4564 (1984);Google Scholar
van Kooten, JJ., Ph.D. Thesis, Amsterdam (1987)Google Scholar
and Chantre, A. and Bois, D., Phys. Rev. B31, 7979 (1985).Google Scholar
19. For a theoretical treatment see Scheffler, Matthias, Festkörperprobleme 29, 231 (1989).Google Scholar