Dispersive Effects in Microwave AlGaN/AlN/GaN HEMTs With Carbon-Doped Buffer
2015 (English)In: IEEE Transactions on Electron Devices, ISSN 0018-9383, Vol. 62, no 7, 2162-2169 p.Article in journal (Refereed) Published
Aluminium gallium nitride (AlGaN)/GaN high-electron mobility transistor performance is to a large extent affected by the buffer design, which, in this paper, is varied using different levels of carbon incorporation. Three epitaxial structures have been fabricated: 1) two with uniform carbon doping profile but different carbon concentration and 2) one with a stepped doping profile. The epitaxial structures have been grown on 4H-SiC using hot-wall metal-organic chemical vapor deposition with residual carbon doping. The leakage currents in OFF-state at 10 V drain voltage were in the same order of magnitude (10-4 A/mm) for the high-doped and stepped-doped buffer. The high-doped material had a current collapse (CC) of 78.8% compared with 16.1% for the stepped-doped material under dynamic I-V conditions. The low-doped material had low CC (5.2%) but poor buffer isolation. Trap characterization revealed that the high-doped material had two trap levels at 0.15 and 0.59 eV, and the low-doped material had one trap level at 0.59 eV.
Place, publisher, year, edition, pages
IEEE Press, 2015. Vol. 62, no 7, 2162-2169 p.
Gallium nitride, HEMTs, trap levels, current collapse, dispersion
IdentifiersURN: urn:nbn:se:liu:diva-117136DOI: 10.1109/TED.2015.2428613ISI: 000356457900014OAI: oai:DiVA.org:liu-117136DiVA: diva2:805919