| Autor: |
Kasper, E., Burle, N., Escoubas, S., Werner, J., Oehme, M., Lyutovich, K. |
| Předmět: |
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| Zdroj: |
Journal of Applied Physics; Mar2012, Vol. 111 Issue 6, p063507, 10p |
| Abstrakt: |
Metastable and strain relaxed SiGe layers with about 20% Ge content have been grown by molecular beam epitaxy on Si substrates at 550 °C. The thickness regime of metastability and the onset of strain relaxation were investigated on dust particle free surfaces obtained by careful chemical cleaning and epitaxy loading under clean room conditions. Compared to earlier results true metastable regime without misfit dislocations was obtained up to 140 nm thickness. The onset of strain relaxation started with heterogeneous nucleation sites of misfit dislocations. X-ray topography proved to be a unique monitoring tool to observe a low density of single dislocations. From these results we suggested to define a critical thickness band with lower bound tcl from dislocation nucleation to an upper bound tco (600 nm in our case) defined by the onset of considerable strain relaxation. The strain relief was measured by X-ray diffraction (reciprocal space mapping) and found to be very abrupt (76% strain relaxation at 800 nm thickness). [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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