SiC同质外延材料表面形貌缺陷研究

Study on Surface Morphology Defects in 4H-SiCHomoepitaxial

本文针对SiC同质外延材料中的表面形貌缺陷展开研究,使用共聚焦表面缺陷分析仪对外延材料表面缺陷进行表征测试和统计。根据三角形缺陷的结构和形貌特征,分析三角形缺陷的产生机制和延伸模型,系统研究了刻蚀气体HCl流量对SiC外延材料表面三角形缺陷的影响,结果表明刻蚀气体流量和时间对三角形缺陷影响明显,在HCl流量为100mL/min时,4英寸SiC外延材料表面三角形缺陷密度最低,达到0.85/cm^(2)。结合KOH腐蚀工艺,研究胡萝卜位错的产生机理,通过优化SiC外延生长速率,实现SiC外延材料胡萝卜缺陷密度有效降低至0.2/cm^(2)以下。

This paper studies the surface morphology defects in 4 H-SiC epitaxial materials, and uses a confocal microscope with differential interference contrast to characterize the surface morphology defects of 4 H-SiC. According to the structural and morphological characteristics of triangular defects, it analyzes the generation mechanism and extension model and investigates the influence of pre-etching HCl flow on the triangular defects of SiC epilayers. The triangular defects density of 0.85 cm^(-2) is achieved with a pre-etching HCl flow of 100 mL/min. In addition, it studies the mechanism of the carrot defects using KOH etching process. By optimizing the SiC epitaxial growth rate, the carrots defects density is effectively reduced to lower than 0.2 cm^(-2).