Relationship between defects induced by irradiation and reduction of hole concentration in Al-doped 4H–SiC

✍ Scribed by Hideharu Matsuura; Sou Kagamihara; Yuji Itoh; Takeshi Ohshima; Hisayoshi Itoh

• Publisher: Elsevier Science
• Year: 2006
• Tongue: English
• Weight: 144 KB
• Volume: 376-377
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/j.physb.2005.12.088

✦ Synopsis

From the temperature dependence of the hole concentration in lightly Al-doped 4H-SiC epilayers, a shallow acceptor with E V þ 0:2 eV, which is an Al atom ðAl Si Þ at a Si sublattice site, and an unknown deep defect with E V þ 0:35 eV are found, where E V is the valence band maximum. In unirradiated epilayers, moreover, the density ðN Defect Þ of this defect is close to the Al acceptor density ðN Al Þ. With irradiation of 0.2 MeV electrons, the N Al is reduced, while the N Defect is increased. Judging from the minimum electron energy required to displace a substitutional C atom ðC s Þ or Al Si , the bond between Al Si and its nearest neighbor C s is broken due to the displacement of the C s by this irradiation. Moreover, the displacement of the C s results in the creation of a complex ðAl Si 2V C Þ of Al Si and its nearest neighbor C vacancy ðV C Þ, indicating that the possible origin of the defect with E V þ 0:35 eV is Al Si 2V C .