The influence of band offsets on the IV characteristics for GaN/SiC heterojunctions
2002 (English)In: Solid-State Electronics, ISSN 0038-1101, E-ISSN 1879-2405, Vol. 46, no 6, 827-835 p.Article in journal (Refereed) Published
GaN/SiC heterojunctions can improve the performance considerably for bipolar transistors based on SiC technology. In order to fabricate such devices with a high current gain, the origin of the low turn-on voltage for the heterojunction has to be investigated, which is believed to decrease the minority carrier injection considerably. In this work heterojunction diodes are compared and characterized. For the investigated diodes, the GaN layers have been grown by molecular beam epitaxy (MBE), metal organic chemical vapor deposition, and hydride vapor phase epitaxy. A diode structure fabricated with MBE is presented here, whereas others are collected from previous publications. The layers were grown either with a low temperature buffer, AIN buffer, or without buffer layer. The extracted band offsets are compared and included in a model for a recombination process assisted by tunneling, which is proposed as explanation for the low turn-on voltage. This model was implemented in a device simulator and compared to the measured structures, with good agreement for the diodes with a GaN layer grown without buffer layer. In addition the band offset has been calculated from Schottky barrier measurements, resulting in a type II band alignment with a conduction band offset in the range 0.6-0.9 eV. This range agrees well with the values extracted from capacitance-voltage measurements.
Place, publisher, year, edition, pages
2002. Vol. 46, no 6, 827-835 p.
GaN/SiC heterojunction, band offset, midgap theory, schottky-barrier height, bipolar junction transistors, n-p heterojunctions, metal contacts, power devices, gan, dependence, carbide, diodes
IdentifiersURN: urn:nbn:se:kth:diva-21574ISI: 000175817800008OAI: oai:DiVA.org:kth-21574DiVA: diva2:340272
QC 201005252010-08-102010-08-10Bibliographically approved