Defect formation during Zn diffusion in GaP and GaSb

The defect structures induced by zinc diffusion in intrinsic GaP single cry stals at temperatures between 1182K and 1358K and in an intrinsic GaSb sing le crystal at 883K are characterized for diffusion times t less than or equ al to 90 min by analytical transmission electron microscopy. The results ar e compared with Zn concentration depth profiles obtained by secondary ion m ass spectroscopy. In regions near the Zn diffusion front dislocation loops of interstitial type and Ga-rich precipitates are found. Closer to the surf ace a loose network of dislocations, dislocation loops and faceted voids wi th Ga-rich precipitates are observed. In addition, a surface layer of polyc rystalline Zn3P2 is formed at the surface of GaP at higher diffusion temper atures. The formation of diffusion-induced defects can be understood in a s imilar way as the defect formation during Zn diffusion in GaAs and InP.