Si基GaN外延层光致发光光谱与二次离子质谱的研究

报道了在Si基上用简便的真空反应法制备出GaN外延层．光致发光光谱测试结果表明不同的生长温度和退火工艺会对GaN外延层的发光特性产生影响，在1050℃下生长的GaN外延层的发光强度高于其他温度下生长的发光强度，退火可以使GaN外延层的发光强度增强．二次离子质谱(SIMS)测试结果表明外延层中Ga和N分布均匀，在表面处Ga发生了偏聚，同时外延层中还存在Si，O等杂质，这使得外延层中背景电子浓度高达1.7×10¹⁸/cm³. SIMS测试结果还表明，在外延生长前采用 关键词：

SECONDARY ION MASS SPECTROSCOPY AND PHOTOLUMINESCENCE INVESTIGATIONS ON THE GaN EPILAYER GROWN ON Si SUBSTRATE

In this paper, the growth GaN epilayer on the Si substrate by a novel vacuum reaction method rather than metal-organic chemical vapor deposition and moleculau beam epitaxy is reported. The effects of growth temperature and annealing process on the photoluminescence (PL) of GaN epilayer were investigated. Annealing could weaken the PL and the GaN epilayer grown at 1050℃ exhibited the strongest PL. It was demonstrated in secondary ion mass spectroscopy that both gallium and nitrogen were distributed uniformly within the epilayer, while gallium was segregated on the surface of epilayer. The high carrier concentration (1.7×10¹⁸/cm³) was associated with the impurities of silicon and oxygen and native defects existing in the epilayer. In-situ cleaning was proved to be efficient for the removal of oxygen on the silicon substrate.