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采用金属有机物化学气相淀积方法在Al2O3衬底上生长不同浓度Mg掺杂的AlxGa1-xN合金薄膜,并在750℃、N2气氛下对Mg进行热退火激活。用X射线衍射ω-2θ扫描计算确定样品的Al组分,发现Mg摩尔掺杂浓度和退火对Al组分均未产生明显影响。X射线衍射摇摆曲线与原子力显微镜扫描表明随Mg摩尔掺杂浓度增加,样品晶体质量下降,样品表面凹坑增加,但热退火对薄膜表面形貌有明显的改善。阴极射线发光测量发现带边峰强度随掺杂浓度增加而减弱,退火后样品的施主-受主对复合发射与导带受主的复合发射均有增强,验证了热退火对钝化受主杂质的激活作用,对实现高效AlGaN的p型掺杂具有重要意义。
The Mg-doped AlxGa1-xN alloy thin films with different concentrations were grown on the Al2O3 substrate by metal-organic chemical vapor deposition. The Mg was heat-annealed at 750 ℃ in N2 atmosphere. The Al composition of the sample was determined by X-ray diffraction analysis of the ω-2θ scan. It was found that the Mg molar doping concentration and the annealing did not significantly affect the Al composition. X-ray diffraction rocking curve and atomic force microscopy scanning showed that with the increase of Mg molar doping concentration, the sample crystal quality decreased, the sample surface pits increased, but the thermal annealing of the film surface morphology has significantly improved. It was found by the measurement of cathodoluminescence that the band edge intensity decreased with the increase of the doping concentration, and the donor-acceptor composite emission and the conduction band acceptor composite emission increased after annealing, which verified the effect of thermal annealing on passivated acceptor impurity The activation of p-type AlGaN is of great significance.