Defect formation during Zn diffusion in GaP and GaSb

Abstract

The defect structures induced by zinc diffusion in intrinsic GaP single crystals at temperatures between 1182K and 1358K and in an intrinsic GaSb single crystal at 883K are characterized for diffusion times t ≤ 90 min by analytical transmission electron microscopy. The results are compared with Zn concentration depth profiles obtained by secondary ion mass spectroscopy. In regions near the Zn diffusion front dislocation loops of interstitial type and Ga-rich precipitates are found. Closer to the surface a loose network of dislocations, dislocation loops and faceted voids with Ga-rich precipitates are observed. In addition, a surface layer of polycrystalline Zn 3 P 2 is formed at the surface of GaP at higher diffusion temperatures. The formation of diffusion-induced defects can be understood in a similar way as the defect formation during Zn diffusion in GaAs and InP.