Criterion for blocking threading dislocations by strained buffer layers in GaAs grown on Si substrates

Abstract

An energy model has been used to calculate the minimum critical thickness in strained-layer superlattices that is required to block threading dislocations. The model calculates the total change in the system energy that results from the presence of a bent dislocation segment at the strained interface. The calculations show that a threading dislocation has to overcome an energy barrier before gliding along the strained-layer interface becomes favorable. The model predicts that the process of blocking threading dislocations by strained-layer structures can be thermally activated.