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利用水平式低压热壁CVD(LP-HW-CVD)生长系统,台阶控制生长和衬底旋转等优化技术,在偏晶向的4H-SiCSi(0001)晶面衬底上进行4H-SiC同质外延生长,生长温度和压力分别为1550℃和104Pa,用高纯N2作为n型掺杂剂的4H-SiC原位掺杂技术,生长速率控制在5μm/h左右.采用扫描电镜(SEM)、原子力显微镜(AFM),傅里叶变换红外光谱(FTIR)和Hg/4H-SiC肖特基结构对同质外延表面形貌、厚度、掺杂浓度以及均匀性进行了测试.实验结果表明,4H-SiC同质外延在表面无明显缺陷,厚度均匀性1.74%,1.99%和1.32%(σ/mean),掺杂浓度均匀性为3.37%,2.39%和2.01%.同种工艺条件下,样品间的厚度和掺杂浓度误差为1.54%和3.63%,有很好的工艺可靠性.
4H-SiC homogenization on 4H-SiCSi (0001) crystal plane substrate in the orthorhombic direction was carried out by using LP-HW-CVD growth system, step controlled growth and substrate rotation optimization. The growth rate and growth rate of 4H-SiC were controlled at 5μm / h by epitaxial growth, growth temperature and pressure at 1550 ℃ and 104Pa, respectively, using high-purity N2 as n-type dopant.Using scanning electron microscopy The morphology, thickness, doping concentration and homogeneity of homoepitaxial surface were tested by atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR) and Hg / 4H-SiC Schottky structure.The experimental results show that 4H -SiC homoepitaxy has no obvious defects on the surface, the thickness uniformity is 1.74%, 1.99% and 1.32% (σ / mean), the doping concentration uniformity is 3.37%, 2.39% and 2.01% Between the thickness and doping concentration error of 1.54% and 3.63%, with good process reliability.