Characteristics of InP on GaAs substrate using Zn-doped Al(Ga)InAs metamorphic buffers

We have investigated the effects of Zn doping on the surface morphology and the dislocation movement of the metamorphic Al(Ga)InAs buffers grown by metal–organic chemical vapor deposition (MOCVD) on (001) GaAs substrate with 15° miscut toward (111)A. It is found that surface morphology and roughness are governed by the amount of In atoms and their diffusion on the surface, and Zn-doping suppresses the In segregation to weaken the formation of phase separation which prevents the dislocations gliding and increases the threading dislocation density. In addition, the strong bond strength between Zn impurity atoms and sublattice site atoms plays an important role for dislocation motion. In other words, propagating dislocation in Al(Ga)InAs metamorphic buffers will be stopped at a position adjacent to the Zn impurities to decrease the interaction between the surface morphology and dislocation pile-up to reduce the threading dislocation density in InP layer.