A study on the heat treatment process for AlN single crystals grown by PVT method

AlN single crystal was thermally treated at 1600, 1700 and $1800^{\circ}C$ in the ambient pressure of under 100 torr. AlN single crystal was obtained by PVT (Physial Vapor Transport) method using by a facility having a growth part which was heated by RF (Radio Frequency) induction heating. The single crystal specimens surface was evaluated by optical microscope and it was recognized that their morphology was varied with the heat treatment temperature and a set ambient pressure. In this report, the optical microscopic results were reported. According to the increase of temperature the crystal surface was etched thermally. It was evaluated by appearance of small pits on the crystal surface.

PVT 법으로 성장된 AlN 단결정의 열처리 공정에 대한 연구

AlN 단결정을 $1600{\sim}1800^{\circ}C$의 온도에서 100 torr 이하의 진공하에서 $100^{\circ}C$ 간격으로 열처리하였다. AlN 단결정은 고주파유도가열 방식으로 가열되는 성장부를 갖는 성장장치를 사용하여 PVT법으로 얻어내었다. 단결정 시편들의 표면을 광학현미경으로 관찰하였으며, 성장된 압력 하에서 온도에 따라 형상이 달라짐을 알 수 있었다. 본 연구에서는 광학현미경 관찰 결과를 보고하고자 하며, 열처리 온도가 증가함에 따라 표면의 열에칭이 나타났는데, 이는 작은 에치핏의 형성을 통하여 관찰하였다.