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Oxygen vacancy defects in tantalum pentoxide: a density functional study

Published online by Cambridge University Press:  11 February 2011

R. Ramprasad ,
Michael Sadd ,
Doug Roberts ,
Tom Remmel ,
Mark Raymond ,
Eric Luckowski ,
Sriram Kalpat ,
Carole Barron  and
Mel Miller
R. Ramprasad
Affiliation:
Motorola Semiconductor Products Sector, 2100 E. Elliot Rd., Tempe, AZ 85284
Michael Sadd
Affiliation:
Motorola Semiconductor Products Sector, 3501 Ed Bluestein Blvd, Austin, TX 78721
Doug Roberts
Affiliation:
Motorola Semiconductor Products Sector, 3501 Ed Bluestein Blvd, Austin, TX 78721
Tom Remmel
Affiliation:
Motorola Semiconductor Products Sector, 2100 E. Elliot Rd., Tempe, AZ 85284
Mark Raymond
Affiliation:
Motorola Semiconductor Products Sector, 2100 E. Elliot Rd., Tempe, AZ 85284
Eric Luckowski
Affiliation:
Motorola Semiconductor Products Sector, 3501 Ed Bluestein Blvd, Austin, TX 78721
Sriram Kalpat
Affiliation:
Motorola Semiconductor Products Sector, 3501 Ed Bluestein Blvd, Austin, TX 78721
Carole Barron
Affiliation:
Motorola Semiconductor Products Sector, 3501 Ed Bluestein Blvd, Austin, TX 78721
Mel Miller
Affiliation:
Motorola Semiconductor Products Sector, 2100 E. Elliot Rd., Tempe, AZ 85284
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Abstract

First principles total energy calculations were performed in order to characterize O vacancy defects in Ta2O5. A simplified version of the crystalline orthorhombic phase of Ta2O5 was used in this study. Results indicate that O vacancies in Ta2O5 can be broadly classified based on their location in the lattice. One type of vacancies (occupying the “in-plane” sites) displays deep or mid gap occupied states, and shallow unoccupied states, while a second type (occupying “cap” sites) results in shallow occupied states. For a wide range of local Fermi level or chemical potential, the neutral and +2 charged states of the in-plane type vacancy and the +2 charge state of the cap type vacancy are found to be most stable. Migration energies of the two types of vacancies in the neutral and +2 charge states are markedly different, with the “cap” type of vacancies displaying very high barriers to migration (∼ 5 eV) compared to the “in-plane” type (∼ 0.5–1.0 eV).

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 745: Symposium N – Novel Materials and Processes for Advanced CMOS , 2002 , N7.6/T5.6
Copyright
Copyright © Materials Research Society 2003

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References

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