In situ observation of LPE growth process of aluminum nitride for understanding the dislocation formation mechanism

点击翻译按钮获取中文摘要

The growth process of AlN from Al-Ga flux at high temperature was observed in-situ. The dislocation formation, which leads to the formation of low quality AlN, is strongly dependent on the AlN nucleation process on the substrate. On the sapphire substrate, AlN crystals formed by heterogeneous nucleation. Each of the crystal, which has mismatched crystallographic orientation, grows by coalescence growth mechanism. This growth process resulted in low quality AlN crystal with high dislocation density. On the other hand, AlN crystals grow homo-epitaxially on the nitride sapphire substrate. And the coalescence growth was suppressed on the nitride sapphire. These growth mechanisms resulted in the high quality AlN formation on nitride sapphire substrate.