| Compared with recently semiconductor materials, Ga N HEMT has some features, such as wide bandgap, large density, high breakdown electric field and so on. It shows a enormous potential in the field of high temperature, high frequency and high power applications. However, they also have many shortages, such as the larger gate leakage current and current collapse, which is consequently inhibiting device commercialization.In order to reduce the gate leakage current, the mos-structure is added to the HEMT device. However, as the size of device reducing, the gate dielectric thickness also needs to be reduced, the resulting quantun tunneling effect will increase gate leakage current. The use of high κ dielectric as the gate dielectric of Ga N HEMT devices can improve frequency characteristics and reduce the gate leakage,and has become the trend of development in recent years.In the paper, the design and performance optimization of high κ Al Ga N/Ga N MOS-HEMT device are studied. The device model is based on ISE-TCAD simulation platform, and this paper mainly research on device’s optimization and breakdown characteristics, The main work and conclusions are as follows:Firstly, this paper takes the simulation for MOS structure HEMT, and analyzes the different dielectric layer thickness and high κ stack gate on the MOS-HEMT properties. The results indicate that the MOS structure can decrease the gate leakage current, but its gate control ability was reduced. The decrease of oxide thickness can improve the transconductance and the gate control ability as well as the high κ stack gate structure.The breakdown character of HEMT device is also studied by simulation, high κ stack gate structure can improve breakdown voltage. So we use the structure to study the effects of different parameters of breakdown characteristics are analyzed. It is found that the increase of Lgd can gradually broaden the peak value and improve the breakdown voltage. Because the Al component of channel improve the band gap, it also improve the breakdown voltage. The presence of trap charge, the peak value of gate will be weakened, which will lead to the breakdown of drain. The reason of the field plate to improve the HEMT’s breakdown voltage is analyzed by simulation results. According to optimize the geometrical variables, the breakdown voltage reaches the maximum. Finally, It proves that multiple field plate can effectively improve the breakdown voltage. |
