Defect levels in low-doped 4H-SiC Schottky barrier diodes detected by using alpha particles

Iwamoto, Naoya; Johnson, B. C.; Hoshino, Norihiro*; Ito, Masahiko*; Tsuchida, Hidekazu*; Oshima, Takeshi

Defects in Schottky barrier diodes (SBDs) formed on low-doped 4H-silicon carbide (SiC) have been studied by charge transient spectroscopy using single high energy alpha particles as the trap filling pulse. We have successfully detected defect levels in as-fabricated, electron-irradiated and thermally annealed SBDs where the high series resistance precludes the use of standard techniques such as Deep Level Transient Spectroscopy (DLTS). It was found that carrier capture cross sections of detected defect levels are as large as 10 cm. These defect levels, which have large capture cross sections, are the most important since they tend to dominate recombination processes in devices.