Thermal Resistance Extraction And Microwave Modeling Of GaN High Electron Mobility Transistor Under High Self-heating Bias

The microwave devices based on the third generation of wide bandgap semiconductor material gallium nitride(GaN)are particularly suitable for producing high frequency,high voltage and high power microwaves devices because of their prominent characteristics such as large band gap,high thermal conductivity,and high electron saturation drift speed,and the microwave devices have wide prospects in the fields of military applications and civilian applications.Gallium nitride-based high electron mobility transistors(GaN HEMT)have great advantages in operating frequency and gain.Dissipation of power in GaN HEMT devices results in a rise in channel temperature which in turn leads to a decrease in electron mobility and electron saturation rate,ultimately limits the maximum output current and power conversion efficiency.In addition,the channel temperature also closely related to the stability and lifetime of the device.In this context,the HEMT device model is constructed using TCAD simulation tools,the self-heating effect of the device is studied,the thermal resistance of the device is calculated,and the optimal design of the device and the nonlinear model are discussed.The main contents of this thesis include: 1)The physical structure and basic principle of operation of GaN HEMT devices are introduced,the self-heating effect of the device on the working efficiency and output characteristics of the device are analyzed;2)Several methods for extracting the thermal resistance of RF devices are introduced,a method for directly extracting the device thermal resistance based on a high self-thermal bias region is applied to a GaN HEMT device by comparison;3)A GaN HEMT device model with gate width of 250 ?m and gate length of 0.25 ?m is constructed in TCAD software,the output characteristics at different temperatures are simulated and the thermal resistance of the device is directly calculated with formula derived;4)Taking the thermal resistance of GaN HEMT devices as the research object,the influence of the structural and non-structural factors of the device on the thermal resistance of the device was analyzed,and the optimization of the GaN HEMT device was analyzed and designed;5)The nonlinear model EEHEMT of HEMT device is studied.The thermal resistance extracted by this thesis is embedded in it,and the thermal model in the model is perfected.The fitting result proves that the precision of the model is greatly improved.