Dislocation Sidewall Gettering in II-VI Semiconductors and the Effect of Dislocation Pinning Interactions

It has been shown that threading dislocations may be removed from patterned mismatched heteroepitaxial layers through a process of dislocation sidewall gettering (DSG), also known as patterned heteroepitaxial processing (PHeP). This gettering approach involves the glide of dislocations toward sidewalls, where they become trapped by image forces. Simple quantitative models have been developed for DSG, but they fail to explain why only partial removal of dislocations was observed in ZnSSe/GaAs (001) whereas complete removal has been achieved in ZnSe/GaAs (001) with higher lattice mismatch. Until now this phenomenon has been qualitatively explained by the presence of sessile dislocations. Here we present a quantitative model for pinning interactions and show that these interactions can limit the growth of misfit dislocation segments and thereby reduce the effectiveness of DSG in ZnS y Se 1-y /GaAs (001) relative to ZnSe/GaAs (001).