Dislocation distribution in a strain-relaxed SiGe thin film grown on an ion-implanted Si substrate

We produced a strain-relaxed SiGe thin film on a Si substrate using the method we proposed recently: we implanted Ar ions into Si substrates and then grew 100-nm-thick Si0.8Ge0.2 at 500 °C by the solid source molecular beam epitaxy method followed by an annealing at 900 °C for 2 h. Then we observed the distribution of dislocations both in the SiGe and Si from three different crystallographic directions by transmission electron microscopy. There are threading dislocations in the SiGe layer. However, it was also revealed that a large number of dislocations were localized around the SiGe/Si interface and it can be concluded that the dislocations around the interface mainly contribute to relax the SiGe.