Growth and characterization of strain-relaxed SiGe buffer layers on Si(0Â 0Â 1) substrates with pure-edge misfit dislocations

We report a method to form strain-relaxed SiGe buffer layers on Si(0 0 1) substrates with pure-edge dislocations. Since the Burgers vector of the pure-edge dislocation has only one-edge component along one of the in-plane 〈110〉 directions, it is expected that mosaicity and surface roughening are suppressed in the SiGe buffer layer relaxed with pure-edge dislocations at the SiGe/Si(0 0 1) interface. In order to form such layers, epitaxial or amorphous Si is deposited on a thin Ge layer which has a network of pure-edge dislocations at the Ge/Si(0 0 1) substrate interface, followed by high-temperature annealing for forming intermixed SiGe layers. We confirmed that the network structure was preserved after the high-temperature annealing. The obtained SiGe buffer layers exhibit less mosaicity and have flat surfaces with root mean square values less than 1 nm.