Modelling and Simulation of Normally-off AlGaN/GaN MOS-HEMTs

Andrzej Taube, Mariusz Sochacki, Jan Szmidt, Eliana Kamińska, Anna Piotrowska


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- 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 5x1015 cm-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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