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

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-κ 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 5×10¹⁵cm⁻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.