Assessing the delay of plastic relaxation onset in SiGe islands grown on pit-patterned Si(001) substrates

The onset of plastic relaxation in SiGe islands grown on pit-patterned Si(001) substrates is investigated using elasticity theory solved by finite element methods. Larger critical island volumes with respect to the unpatterned case are predicted. A justification based on the qualitatively different stressors acting on the substrate in the presence of pits is provided. Experimental results in terms of critical SiGe-island volumes as a function of the Ge content are nicely reproduced by the model. (C) 2011 American Institute of Physics. [doi:10.1063/1.3615285]