Study of Si(111) Implanted with As Ions by X-Ray Diffraction and Grazing Incidence Methods |
| J.B. Pełka, J. Górecka, J. Auleytner, J. Domagała and J. Bąk-Misiuk Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland |
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| The Si(111) wafer cut from a bulk single crystal obtained by the Czochralski method was implanted with 5×1016 I cm-2 of As ions of energy 80 keV. The dose applied was chosen above the amorphization limit of the silicon substrate. Two samples, implanted and a reference, were studied by grazing incidence X-ray reflectometry and X-ray diffraction methods using a high resolution Philips MRD system equipped with a Cu source and a channel-cut monochromator. The obtained spectra were compared with distributions of ion range and defect production calculated with TRIM program [1], as well as with theoretical models of reflectivity [2, 3]. The results of grazing incidence X-ray reflectometry reflectivity of the implanted sample show well-pronounced oscillations, which can be associated with a layer about 50 nm thick, approximately comparable to the thickness of the defected layer estimated from the TRIM method. Theoretical calculations of reflectivity clearly indicate an occurrence of a Si layer of electron density lower about 10-15% comparing to the unimplanted Si sample. This can be due to the vacancy production during ion implantation. A comparison of the spectra with a density distribution profile concluded from the TRIM calculations shows large discrepancies. The results indicate the applicability of grazing incidence X-ray reflectometry method in a study of amorphization processes in implanted layers. |
| DOI: 10.12693/APhysPolA.91.905 PACS numbers: 68.55.Jk, 68.55.Ln |