Edwardson, C. J., Coleman, P. G., El Mubarek, H. A. W. and Gandy, A. S., 2012. Positron annihilation studies of fluorine-vacancy complexes in Si and SiGe. Journal of Applied Physics, 111 (7), 073510.
The formation of fluorine-vacancy (FV) complexes in strained Si-SiGe-Si multilayer structures and relaxed SiGe layers of varying Ge content has been investigated using variable-energy positron annihilation spectroscopy, including Doppler-broadened spectra ratio curves. It has been found that in all sample types there are two distinct regions defined only by the damage created by the implanted F ions. The first, shallower region (from the surface to a depth of ∼200 nm) was found to contain a mixture of undecorated vacancies and FV complexes; there is no correlation between the vacancy or F concentration in this region and the Ge content. The multi-layer samples may also have O contamination that is not present in the relaxed samples. The second region (at depths ∼200–440 nm) contains primarily FV complexes in all samples. In the multi-layer samples secondary ion mass spectrometry (SIMS) results show peaks of F accumulating in, or at the interfaces of, each SiGe multi-layer; the FV complexes, however, are distributed over depths similar to those in the relaxed samples, with some localization at the SiGe layer located within the second region. The positron response is primarily to FV complexes formed by the F implant in all samples. The F: FV ratios are approximately 3–7: 1 in the relaxed samples. Positrons appear to be relatively insensitive to the largest of the F SIMS peaks which lies beyond the second region. This is probably because the F has filled all the open volume at the SiGe layer, leaving no positron trapping sites.
|Item Type ||Articles|
|Creators||Edwardson, C. J., Coleman, P. G., El Mubarek, H. A. W. and Gandy, A. S.|
|Departments||Faculty of Science > Physics|
|Publisher Statement||Edwardson_JAP_2012_111_073510.pdf: Copyright (2012) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Edwardson, C. J., Coleman, P. G., El Mubarek, H. A. W. and Gandy, A. S., 2012. Positron annihilation studies of fluorine-vacancy complexes in Si and SiGe. Journal of Applied Physics, 111 (7), 073510 and may be found at http://dx.doi.org/10.1063/1.3699314|
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