Gan Hemts Device Modeling And Simulation

Microwave power transistor is the critical part of modern systems ranging from commercial wireless communication to military radar. As the requirement is increasing, the second generation such as GaAs, due to its limitations, cannot keep pace with the demand for improment. AlGaN/GaN HEMT, which based on the third generation wide band gap semiconductor GaN material, have been demonstrated for applications in high frequency, high power and promise to become the research focus for future.In this thesis, by fully understanding the development of AlGaN/GaN HEMT and mastering the principle of the AlGaN/GaN HEMT, we developed the simple HEMT model. Then we optimize the model through simulation and analysis. Major work can be summarized as the following aspects:1. We model the AlGaN/GaN HEMT, design the device and physics parameters, and then simulate the device with the ISE, specific analysis the carrier distribution, electric distribution, electric potential distribution etc. The specific details described in chapterⅢsection 3.1.2. We qualitative analysis the gate leakage current of AlGaN/GaN HEMT, then optimize the device based on the maximum electric field from several aspects: lag the distance of gate and drain, adjust the barrier layer thickness and doping concentration, adjust the polarization charge, use the cap layer, use field plate, the surface passivation, etc. The specific details described in chapterⅢsection 3.2.3. We detailed discuss non-linear phenomena of source resistance in the high current mode, then explain the degradation of device performance. The specific details described in chapterⅢsection 3.3.4. We analysis the relationship about stress and strain in the Electromechanical coupled model, and then perfect the formula,at last we got a trixal stress. In the advanced formula, we talked about the changes in the coupled model which under the gate bias, such as the the stress and strain of in-plane and out-plane of the AlGaN barrier layer. At last, we analyzed the impact on the threshold voltage. The specific details described in chapterⅣ.