Defect formation during zinc diffusion in GaP

The defect structure of undoped GaP single crystals following Zn ampoule diffusion between 800 degreesC and 1100 degreesC with metallic Zn and P as sources was observed by transmission electron microscopy for various diffusion conditions. Agglomerates of predominantly perfect interstitial-type dislocation loops, dislocations and small Ga precipitates were observed in the Zn-diffused region. In addition, depending on the diffusion conditions, dislocation networks, Zn-rich precipitates and extrinsic stacking faults were formed. The observations were correlated with Zn concentration profiles obtained from secondary-ion mass spectrometry. The formation, arrangement and temporal evolution of the diffusion-induced defects for P-rich and P-poor diffusion conditions will be discussed and compared with earlier results obtained for Zn diffusion into GaAs and InP.