Study On Characteristic Simulation Of The AlGaN/GaN HEMTs

The semiconductor material GaN with wide bandgap is considered the thirdgeneration semiconductor material. It has been rapid development in recent years.Compared with the most current semiconductor material, GaN has enormous potentialapplications in the field of electronic temperature because of the characteristics of highpressure, high-frequency and high-power. But, the current collapse and breakdownvoltage of the HEMTs become the main factors that obstacles the enhancement of theoutput power. The characteristics of the AlGaN/GaN HEMT device have beenresearched on the Silvaco TCAD-ATLAS platform in this paper.Firstly, the characteristics of GaN materials and AlGaN/GaN heterostructuredevices was analysed in this paper. Secondly, there analyses the working principle ofAlGaN/GaN HEMTs was analysed. Sencodly, a conclusion that polarization effects arethe major motive power of2DEG was proposed. The change of the2DEG concentrationfrom composition of Al and thickness of AlGaN was researched, and the effect ofself-heating was also simulated. Thirdly, the thesis analyses the mechanism of currentcollapse from the float-gate model, back gate effect models and stress models. And thephysical mechanism models of reducing the current collapse was analysed, such assurface passivation techniques, field plate structure and improving the GaN buffer layerand so on. Finally, this paper design different structures of the gate floating compositefield plate AlGaN/GaN HEMTs, and simulate the characteristics of HEMTs.The paper summarizes the optimization law of AlGaN/GaN HEMTs with floatinggatefield plate. And when a field plate with the same effective length, the floating gateplate of composite structure could effectively enhance the breakdown voltage andimprove the frequency characteristics of the device.