4H-SiC外延中的缺陷及其对肖特基二极管的影响

Defect Influence on the Electrical Properties of 4H-SiC Schottky Diodes

研究了4H-SiC外延片中的缺陷对制作出的Ni/4H-SiC肖特基势垒二极管的电学性能的影响。SiC的外延生长是通过LPCVD外延设备在偏8°的(0001)Si面4H-SiC单晶片上进行的,衬底材料来自外购,同质生长的SiC外延层掺杂为n型,掺杂浓度5×1015cm-3,厚度为10μm。通过对外延好的4H-SiC片进行2cm×2cm划片,使用扫描电镜(SEM)、原子力显微镜(AFM)及喇曼光谱多种测试手段对边长为2cm的方形SiC外延材料的表面形貌、缺陷和晶型进行了分析研究,制作了简单的Ni/4H-SiC肖特基势垒二极管,制造的二极管为直径110μm的圆形。简述了制作肖特基势垒二极管的相关工艺流程;通过电学测试得到了性能较好的特性参数为理想因子n=1.24,势垒高度=0.87eV,击穿电压在650V。

The defect influence of n-type 4H-SiC epitaxial layer on the electrical properties of Ti/4H-SiC Schottky barrier diode(SBD)was reported.The wafer is commercially available.The surface,defect and the polytype of the 2 cm×2 cm SiC epilayer were anlyzed with the measurements of SEM,AFM and Raman spectrum.The 4H-SiC epitaxial layer was grown on the commercially available 8°off-oriented Si-face(0001)single-crystal 4H-SiC wafers.Ti/4H-SiC SBDs with the diameter of 110 μm and blocking voltage of 650 V were made on a low n-doped epilayer with a thickness of 10 μm and 5×1015 cm-3 in carrier density.The ideality factor n=1.24 and the effective barrier height =0.85 V of the Ti/4H-SiC SBDs are measured with method of forward density-voltage.