The use of thickness graded samples to investigate the elastic to plastic relaxation in ZnSe/GaAs(001)

The strain relaxation process of ZnSe grown by molecular beam epitaxy on Ga As(001) has been studied using high resolution x-ray diffraction. One singl e sample with a tailored thickness gradient has been used, allowing us to c ontinuously follow the strain in a wide range of thicknesses. The relaxatio n starts around 1300 Angstrom with the coexistence of fully strained and pa rtially relaxed regions of the ZnSe and continues up to 1600 Angstrom. Thes e findings can be explained by the formation of misfit dislocations on the top surface with subsequent migration to the ZnSe/GaAs interface. (C) 1999 American Institute of Physics. [S0003- 6951(99)05440-6].