Prominent defects in semi-insulating SiC substrates

✍ Scribed by N.T. Son; P. Carlsson; A. Gällström; B. Magnusson; E. Janzén

• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 325 KB
• Volume: 401-402
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/j.physb.2007.08.115

✦ Synopsis

Progresses in defects characterization of high-purity semi-insulating (HPSI) SiC substrates are reviewed. The vacancies, divacancy, and carbon vacancy-carbon antisite pairs were found to be dominating defects in HPSI 4H-SiC substrates with the thermal activation energy E a in the range $0.6-1.6 eV. Several vacancy-related deep acceptor levels were estimated and suggested to be responsible for the semiinsulating (SI) behavior in substrates with different E a . Deep levels associated with different activation energies are suggested. Annealing behavior of vacancy-related defects and the stability of the SI properties were studied. Prominent defects in SI 4H-SiC substrates doped with vanadium (V) were identified. Activation energies of E a $1-1.1 eV were observed for V-doped samples with the V concentration ranging from 5.5 Â 10 15 to 1.1 Â 10 17 cm À3 . Our results show that only in heavily V-doped samples, the activation energy E a $1 eV is related to V, whereas in moderate V-doped materials, the SI properties are determined by intrinsic defects.