1 A. Taube is with the Institute of Electron Technology, Al. Lotników 32/46, 02-668 Warsaw, Poland and with Institute of Microelectronics and Optoelectronics, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw, Poland
2 M. Sochacki and J. Szmidt are with Institute of Microelectronics and Optoelectronics, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw, Poland
3 E. Kaminska and A. Piotrowska are with Institute of Electron Technology, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
The article presents the results of modelling and simulation of normally-off AlGaN/GaN MOS-HEMT transistors. The effect of the resistivity of the GaN:C layer, the channel mobility and the use of high-k dielectrics on the electrical characteristics of the transistor has been examined. It has been shown that a low leakage current of less than 10−6 A/mm can be achieved for the acceptor dopant concentration at the level of 5 X 1015cm−3. The limitation of the maximum on-state current due to the low carrier channel mobility has been shown. It has also been demonstrated that the use of HfO2, instead of SiO2, as a gate dielectric increases on-state current above 0.7A/mm and reduces the negative influence of the charge accumulated in the dielectric layer.
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