Estimation of Electron Drift Mobility along the c-Axis in 4H-SiC by Using Vertical Schottky Barrier Diodes

Electron mobility along the c -axis is the most important in SiC because the current flows along this direction in vertical SiC devices. However, previous reports on the drift mobility along the c -axis are still limited because of the difficulty of sample preparation or analysis. In this study, the authors presented the method to estimate the electron drift mobility of a lightly-doped epitaxial layer by using SiC(0001) vertical Schottky barrier diodes (SBDs). For the analyses, the effects of current spreading and series resistance were carefully considered based on experimental results obtained from SBDs with various device parameters, leading to a more accurate estimation. The mobility along the c -axis was obtained as 1070 ± 290 cm 2 /Vs for a donor density of 1 × 10 15 cm -3 , and it was compared with the results by Hall effect measurement.