Hydrogen-induced reversible changes in drain current in Sc2O3/AlGaN/GaN high electron mobility transistors

• Published in: Applied physics letters 2004-06, Vol.84 (23), p.4635-4637
• Main Authors: Kang, B. S., Mehandru, R., Kim, S., Ren, F., Fitch, R. C., Gillespie, J. K., Moser, N., Jessen, G., Jenkins, T., Dettmer, R., Via, D., Crespo, A., Gila, B. P., Abernathy, C. R., Pearton, S. J.
• Format: Article
• Language: English
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.1759372

Pt contacted AlGaN/GaN high electron mobility transistors with Sc2O3 gate dielectrics show reversible changes in drain–source current upon exposure to H2-containing ambients, even at room temperature. The changes in current (as high as 3 mA for relatively low gate voltage and drain–source voltage) are approximately an order of magnitude larger than for Pt/GaN Schottky diodes and a factor of 5 larger than Sc2O3/AlGaN/GaN metal–oxide–semiconductor (MOS) diodes exposed under the same conditions. This shows the advantage of using a transistor structure in which the gain produces larger current changes upon exposure to hydrogen-containing ambients. The increase in current is the result of a decrease in effective barrier height of the MOS gate of 30–50 mV at 25 °C for 10% H2/90% N2 ambients relative to pure N2 and is due to catalytic dissociation of the H2 on the Pt contact, followed by diffusion to the Sc2O3/AlGaN interface.