Improved retention of phosphorus donors in germanium using a non-amorphizing fluorine co-implantation technique

Co-doping with fluorine is a potentially promising method for defect passivation to increase the donor electrical activation in highly doped n-type germanium. However, regular high dose donor-fluorine co-implants, followed by conventional thermal treatment of the germanium, typically result in a dra...

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Bibliographic Details
Published in:Journal of applied physics 2018-04, Vol.123 (16)
Main Authors: Monmeyran, Corentin, Crowe, Iain F., Gwilliam, Russell M., Heidelberger, Christopher, Napolitani, Enrico, Pastor, David, Gandhi, Hemi H., Mazur, Eric, Michel, Jürgen, Agarwal, Anuradha M., Kimerling, Lionel C.
Format: Article
Language:English
Subjects:
Amorphization
Applied physics
Extreme values
Fluorine
Heat treatment
High temperature
Implantation
Implants
Phosphorus
Solid phases
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Summary:Co-doping with fluorine is a potentially promising method for defect passivation to increase the donor electrical activation in highly doped n-type germanium. However, regular high dose donor-fluorine co-implants, followed by conventional thermal treatment of the germanium, typically result in a dramatic loss of the fluorine, as a result of the extremely large diffusivity at elevated temperatures, partly mediated by the solid phase epitaxial regrowth. To circumvent this problem, we propose and experimentally demonstrate two non-amorphizing co-implantation methods; one involving consecutive, low dose fluorine implants, intertwined with rapid thermal annealing and the second, involving heating of the target wafer during implantation. Our study confirms that the fluorine solubility in germanium is defect-mediated and we reveal the extent to which both of these strategies can be effective in retaining large fractions of both the implanted fluorine and, critically, phosphorus donors.
ISSN:0021-8979
1089-7550
DOI:10.1063/1.4999210