Electrical properties of n-GaN/p-SiC and n-AlGaN/p-SiC heterojunction diodes

B. Luo, J. Kim, R. Mehandru, F. Ren, K. P. Lee, S. J. Pearton, A. Y. Polyakov, N. B. Smirnov, A. V. Govorkov, E. A. Kozhukhova, B. Tolmachevsky, A. V. Osinsky, P. E. Norris

Research output: Contribution to journalArticlepeer-review


Properties of n-GaN/p-SiC and n-AlGaN/p-SiC heterojunctions prepared by HVPE on 4H SiC substrates were studied by means of C-V, C/G-T, C-f, I-V and DLTS. It is shown, in agreement with earlier publications, that the GaN/p-SiC HJ is staggered type II with ΔEc=-0.4 eV and ΔEv=0.6 eV. When changing GaN for AlGaN with Al mole fraction of x=0.25-0.3 the band alignment becomes normal type I with ΔEc=0.2 eV and ΔEv=0.6 eV. I-V characteristics of both heterojunctions bear evidence of strong tunneling via defect states, particularly centers with activation energy of 1.25 eV for GaN/4H SiC HJ. The tunneling was found to be more pronounced in the AlGaN/SiC HJs even though these HJs showed no evidence of formation of dark line defects at the interface, in contrast to GaN/SiC. DLTS measurements on both types of HJs revealed the presence of broad bands whose behavior is indicative of these bands being related to continuous states in the gap, most likely near the nitride/carbide interface.

Original languageEnglish
Pages (from-to)335-340
Number of pages6
JournalMaterials Research Society Symposium - Proceedings
Publication statusPublished - 2002
Externally publishedYes

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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