【摘要】 为了制备高品质的SiC外延片，需要降低外延层中的基平面位错(BPD)密度。采用6英寸(1英寸=2.54 cm)水平外延化学气相沉积(CVD)设备分别制备了不同外延厚度的SiC外延片，研究了影响BPD数量的关键因素。结果表明，外延片弯曲度差值和三角形缺陷数量均与BPD数量呈正相关。结合图像观察和应力测试，对外延BPD的形核机理进行了深入研究，建立了缺陷和应力激发BPD延伸形核的模型。外延片弯曲造成的宏观拉应力和三角形缺陷引起的局部拉应力共同激发了衬底中的BPD,促使BPD滑移延伸至外延层中。该研究可为SiC外延片制备过程中BPD的控制提供参考。更多还原

【Abstract】 To prepare high-quality SiC epitaxial wafers, it is necessary to reduce the basal plane dislocation(BPD) density in epitaxial layers. SiC epitaxial wafers with different epitaxial thicknesses were perpared by using a 6 inch(1 inch=2.54 cm) horizontal epitaxial chemical vapor deposition(CVD) device, and the key factors influencing the number of BPD were studied. The results indicate that the bow difference and the number of triangular defect of the epitaxial wafer show a positive correlation with the number of BPD. Combined with image observation and stress test, the nucleation mechanism of epitaxial BPD was deeply studied, and the model for BPD extension and nucleation induced by defect and stress was established. The macroscopic tensile stress resulting from epitaxial wafer bow and the local tensile stress caused by triangular defects jointly activate the BPD in the substrate and promote the slip and extension of BPD into the epitaxial layer. The study can provide reference for the control of BPD in SiC epitaxial wafer preparation process.更多还原