Three-dimensional steady and transient fully coupled electro-thermal simulation of AlGaN/GaN high electron mobility transistors: Effects of lateral heat dissipation and thermal crosstalk between gate fingers

In this paper, we develop three-dimensional fully coupled electro-thermal (ET) simulation for AlGaN/GaN high electron mobility transistors (HEMTs), which is a relative complete and accurate simulation compared to the current existed simulations, capable of describing the lateral ET behavior of the device. As applications of this simulation, we investigate impact of the gate width (WG) and number of the gate fingers (NG) on the steady and transient ET behavior of the device. The steady results show that the lateral heat dissipation and thermal crosstalk between the gate fingers significantly affects the ET behavior for the device with narrow gate and multifinger, respectively. However, the transient results show that, within a time scale after the device switching on, the ET behavior is not influenced by WG and NG, i.e., the lateral heat dissipation and thermal crosstalk have no effects. This indicates that when the device operating in high frequency, increasing WG and NG to improve the power output is not restricted by the self-heating.