Thermal Managemant Of A1GaN/GaN HEMT

Benefit from the heterojunction structure, AlGaN/GaN HEMT has become one of the most potential RF and microwave devices. AlGaN/GaN HEMT's applicability constantly widens in the fields of Satellite Communications, Mobile Communications for its advantages such as high current gain, high cut-off frequency, high driving capability, low phase noise, high power density and so on.However, when HEMT devices working in high-power mode and high temperature environment, the temperature rise caused by conductive channel dissipation power, will result in significant self-heating effect, and what is more it will deteriorate power added efficiency and lower current output capacity.The self-heating effect also will cause degradation of the device RF and microwave performance. And if the self-heating effect is too serious, it may lead to malfunction of the unit. Therefore, the establishment of AlGaN/GaN HEMT two-dimensional thermal model, will help to understand the mechanism of heat generation and heat removal of the power devices, better the thermal management for the AlGaN/GaN HEMT. Having good command of these mechanism and thermal management is surely beneficial for the effective guideness of the design and parameter optimization.This work focuses on the TCAD simulation and 2D modeling of AlGaN/GaN HEMTs device. Based on the model, thermal profiles with single-finger and multi-finger structures are presented in detail and countermeasures concerning thermal management are proposed.First, this paper makes a brief introduction of the material properties of gallium nitride and its research backgrounds. Some fundamentals and principles of the AlGaN/GaN HEMT device are also illustrated in detail. Focused on what is 2DEG and how does 2DEG work, we expound the mechanism of the two-dimensional electron gas with high charge density caused by the polarization effect which exists in the interface between the gallium nitride and aluminium gallium nitride.Next, upon the appropriate electrical, thermal mechanism, AlGaN/GaN HEMT electro-thermal model is established. After the thermal conductivity, heat capacity, thermal resistance model are discussed one by one in detail, some countermeasures about the thermal management are also proposed. At last the significant importance and necessity of the thermal management for the power devices is discussed.Finally, with the aid of the commercial TCAD software, numerical analysis for AlGaN/GaN HEMT has been done. After the comparison between the simulation results and published experimental data, the effectiveness and reasonable accuracy of the model is verified.The simulation results include the AC and DC characteristics, in particular RF characteristics. And on this basis, the paper makes such discussions as the static power consumption and peak temperature distribution channel, the device morphology distribution of the overall relationship between the heat; material parameters and layout parameters on the AC and DC parameters and thermal shape distribution.