We show that suitable pit-patterning of a Si(001) substrate can strongly influence the nucleation and the propagation of dislocations during epitaxial deposition of Si-rich Si1-xGex alloys, preferentially gettering misfit segments along pit rows. In particular, for a 250 nm layer deposited by molecular beam epitaxy at x(Ge) - 15%, extended film regions appear free of dislocations, by atomic force microscopy, as confirmed by transmission electron microscopy sampling. This result is quite general, as explained by dislocation dynamics simulations, which reveal the key role of the inhomogeneous distribution in stress produced by the pit-patterning.
Grydlik, M., Boioli, F., Groiss, H., Gatti, R., Brehm, M., Montalenti, F., et al. (2012). Misfit dislocation gettering by substrate pit-patterning in SiGe films on Si(001). APPLIED PHYSICS LETTERS, 101(1) [10.1063/1.4733479].
Misfit dislocation gettering by substrate pit-patterning in SiGe films on Si(001)
BOIOLI, FRANCESCA;GATTI, RICCARDO;MONTALENTI, FRANCESCO CIMBRO MATTIA;MIGLIO, LEONIDA
2012
Abstract
We show that suitable pit-patterning of a Si(001) substrate can strongly influence the nucleation and the propagation of dislocations during epitaxial deposition of Si-rich Si1-xGex alloys, preferentially gettering misfit segments along pit rows. In particular, for a 250 nm layer deposited by molecular beam epitaxy at x(Ge) - 15%, extended film regions appear free of dislocations, by atomic force microscopy, as confirmed by transmission electron microscopy sampling. This result is quite general, as explained by dislocation dynamics simulations, which reveal the key role of the inhomogeneous distribution in stress produced by the pit-patterning.
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