Abstract
AlN crystals were grown by a sublimation process without seed crystals and the growth morphology of them was characterized. The grown AlN crystals were a polycrystalline phase, which had a diameter of $60\sim200\;{\mu}m$ and were grown with a growth rate of $0.2\sim0.5\;{\mu}n/hr$. It was observed that the as-grown crystals had a hexagonal crystal structure and revealed that these crystals were grown with a morphology of columnar morphology in the initial stage of the growth before they were enlarged in a way of a lateral growth behavior in the final stage. On the surface, a lot of pinholes were observed on the surface of crystals grown. The evolution of a growth morphology was characterized by optical and scanning electron microscopic observation.
종자결정을 사용하지 않고 AlN 결정을 승화법으로 성장하였으며, 결정이 성장되는 양상을 고찰하였다. AlN 결정으로 성장된 상은 다결정 상이었으며, 약 $60\sim160\;{\mu}m$의 크기를 가졌으며, $0.2\sim0.5\;{\mu}m/hr$의 성장 속도로 성장되었다. 성장된 결정구조는 AlN 결정의 결정 구조가 반영된 육방정계의 결정상으로 성장되었음을 관찰하였으며, 주상 구조(columnar structure)로 성장된 후 횡적 성장(lateral growth)하는 양상을 보이면서 대형화됨을 알 수 있었다. 성장된 결정의 표면에서는 다량의 pinhole이 관찰되었으며, 광학현미경과 SEM을 이용하여 성장 morphology의 변화과정을 고찰하였다.