SIMS depth profiling of Mg back-diffusion in (AlGaIn)N light-emitting diodes

The Mg doping profiles in close proximity to the (AlGaIn)N/GaN QW active region of group III-nitride light-emitting diodes grown by low pressure metal-organic vapor-phase epitaxy on sapphire substrates were investigated by secondary ion mass spectrometry (SIMS) depth profiling. The actual Mg profiles close to the active region have been found to be influenced by segregation as well as by back-diffusion during growth and can be controlled by appropriate growth temperatures. From the Mg depth profiles we estimated an activation energy of 4.5-4.7 eV for Mg diffusion in (AlGa)N.