A SIMS study on Mg diffusion in Zn _0.94 Mg _0.06 O/ZnO heterostructures grown by metal organic chemical vapor deposition

Zn _0.94 Mg _0.06 O/ZnO heterostructures have been grown on 2 in. sapphire wafer using metal organic chemical vapor deposition (MOCVD). Photoluminescence (PL) mapping demonstrates that Mg distribution on the entire wafer is very uniform (standard deviation of Mg concentration/mean Mg concentration = 1.38%) with average concentration of ∼6%. The effect of annealing on the Mg diffusion in Zn _0.94 Mg _0.06 O/ZnO heterostructures has been investigated in detail by using secondary ion mass spectrometry (SIMS). All the Mg SIMS depth profiles have been fitted by three Gaussian distribution functions. The Mg diffusion coefficient in the as-grown Zn _0.94 Mg _0.06 O layer deposited at 700 °C is two orders of magnitude lower than that of annealed samples, which clearly indicates that the deposition temperature of 700 °C is much more beneficial to grow ZnMgO/ZnO heterostructures and quantum wells.