SiC籽晶上生长AlN单晶的断裂特性研究

通过扫描电镜(SEM)观察了SiC籽晶上生长AlN单晶的断裂面形貌。模拟了SiC籽晶与AlN晶体之间的应力分布。通过计算不同晶面的面间距，确定了六方晶系的AlN晶体中m面为解理面。拉曼光谱仪对不同晶面的特性进行了表征。结果表明，断裂面为m面，即裂纹扩展并沿m面解理形成断裂面。切割面为c面，AlN沿垂直于c方向生长。拉曼光谱中波数为656.2 cm-1的（E2(high)声子模为AlN单晶中的特征拉曼峰） 声子模式的半高宽为6.5 cm-1，晶体质量高。残余的张应力是裂纹产生的主要原因。

Research on Fracture Characteristics of AlN Crystal Grown on SiC Seed

The fracture surface morphology of AlN single crystal grown on SiC seed crystal was observed by scanning electron microscopy (SEM).The stress distribution between the SiC seed crystal and the AlN crystal was simulated.By calculating the interplanar spacing of different crystal faces, the m plane in the hexagonal AlN crystal was determined as the cleavage plane.The features of different crystal planes were characterized by Raman spectroscopy. The results showed that the fracture plane was m plane, that is, the crack expanded and cleaved along the m plane to form a fracture surface. The cutting planes were the c plane, that is, the AlN was grown along the direction perpendicular to the c axis. The FWHM value of E2(high)phonon mode corresponding to wavenumber of 656.2 cm-1 in Raman spectra was 6.5 cm-1, indicating that the crystalline qualitywas high. The residual tensile stress was the main cause of cracking.