Li Jinlan, Meng Chenxu, Yu Le, Li Yun, Yan Feng, Han Ping, Ji Xiaoli
College of Information Engineering, Yangzhou University, Yangzhou 225009, China.
College of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China.
Micromachines (Basel). 2020 Jun 24;11(6):609. doi: 10.3390/mi11060609.
In this paper, the chemical vapor deposition (CVD) processing for 4H-SiC epilayer is investigated with particular emphasis on the defects and the noise properties. It is experimentally found that the process parameters of C/Si ratio strongly affect the surface roughness of epilayers and the density of triangular defects (TDs), while no direct correlation between the C/Si ratio and the deep level defect Z could be confirmed. By adjusting the C/Si ratio, a decrease of several orders of magnitudes in the noise level for the 4H-SiC Schottky barrier diodes (SBDs) could be achieved attributing to the improved epilayer quality with low TD density and low surface roughness. The work should provide a helpful clue for further improving the device performance of both the 4H-SiC SBDs and the Schottky barrier ultraviolet photodetectors fabricated on commercial 4H-SiC wafers.
本文研究了用于4H-SiC外延层的化学气相沉积（CVD）工艺，特别关注缺陷和噪声特性。实验发现，碳硅比的工艺参数强烈影响外延层的表面粗糙度和三角形缺陷（TDs）的密度，而碳硅比与深能级缺陷Z之间未发现直接关联。通过调整碳硅比，4H-SiC肖特基势垒二极管（SBDs）的噪声水平可降低几个数量级，这归因于具有低TD密度和低表面粗糙度的外延层质量的改善。这项工作应为进一步提高商用4H-SiC晶圆上制造的4H-SiC SBDs和肖特基势垒紫外光电探测器的器件性能提供有益的线索。
