微波毫米波GaN HEMT大信号模型研究

发布时间：2018-04-30 01:34

本文选题：GaN + HEMT　；参考：《电子科技大学》2016年博士论文

【摘要】：氮化镓(GaN)高电子迁移率晶体管(HEMT)以其高频、大功率、高效率等特性优势,成为近年来国内外半导体器件方面研究的热点。GaN HEMT的大信号(或非线性)特性及其模型的研究,在优化器件工艺及结构、指导电路设计和提高电路性能等方面具有重要的指导作用。传统Si及GaAs基场效应晶体管模型及其建模方法,难以精确表征GaN HEMT器件的一些特殊物理特性,如陷阱、自热、谐波和环境温度等特性。精确的微波毫米波GaN HEMT大信号模型对提高器件性能、缩短电路及系统的研发周期、提高成品率、降低成本及推动其大规模系统集成与应用等方面具有重要意义。随着GaN HEMT器件特征尺寸进一步缩小、工作频率和输出功率的提升,以及对电路设计成品率的进一步需求等因素的影响,开展微波毫米波GaN HEMT建模研究对GaN器件和电路的发展有着重要意义。因此,本文针对国产GaN HEMT工艺线,围绕器件工作机理,采用经验基等效电路建模方法,系统地研究了微波毫米波GaN HEMT大信号模型的建模技术。主要研究内容包括:1.超宽带GaN HEMT小信号等效电路模型研究。针对微波毫米波GaN HEMT器件的寄生特性,在传统的晶体管小信号等效电路模型拓扑基础上,增加了栅漏间寄生电阻Rpgd和栅极及漏极端的T型寄生电感,建立了改进的宽带等效电路模型结构,改善了频率低端及高端范围内的小信号S参数拟合精度。在模型元件参数直接提取法基础上,采用了一种基于偏置相关的多维目标误差函数的参数优化方法,克服了传统优化法陷入局部最小值及单一偏置点下优化得出参数值无物理意义的缺点。建立的小信号模型应用于三种不同结构GaN HEMT器件的小信号S参数预测结果表明,在40 GHz宽频带范围内,模型具有较好的精度和通用性。2.微波毫米波GaN HEMT大信号电热模型研究。针对器件材料的非线性热导率特性,采用有限元热仿真方法,建立了以功耗为函数的非线性热子电路模型。针对GaN HEMT非对称跨导等特性,在传统Angelov经验基大信号模型基础上,改进和修正了非线性漏源电流模型和非线性栅电容模型对栅电压的依赖特性,采用了脉冲动态I-V测试技术对GaN HEMT的陷阱效应进行表征,建立了包含自热和陷阱效应的大信号电热模型。与传统大信号模型相比,该大信号模型对DC I-V、输出功率和效率等性能具有更高的预测精度。并基于该建模方法,对不同场板结构的GaN HEMT进行了建模和大信号输出特性分析,进一步验证了模型的准确性和建模方法的有效性。3.高低温GaN HEMT大信号热电模型研究。GaN HEMT常应用于高低温环境的电路与系统中,其电性能不仅受自热效应影响,还随环境温度的变化而改变。本文针对高低温环境电热效应,基于器件电热效应的物理机理及热传递理论,利用有限元热稳态和瞬态仿真方法,分析了自热效应和环境温度对GaN HEMT沟道温度的影响,提取了等效的沟道热阻和热容参数,建立了以环境温度为函数的双热子电路模型,在-55到175 oC环境温度下对沟道温度具有更精确的预测结果。并根据该高低温电热特性,改进了非线性漏源电流和栅电容公式。测试和仿真结果对比表明,该大信号电热模型对高低温环境的小信号S参数、大信号基波、二次谐波和三次谐波输出功率及效率等特性具有较高的预测精度。4.GaN HEMT大信号缩放模型研究。大信号模型的可缩放性是对大尺寸器件建模的重要手段,针对多指器件的热耦合效应和复杂的寄生特性,本文以中等栅宽尺寸的经验基大信号模型为参考,根据GaN HEMT器件栅指数和单位栅宽的物理几何特点,提出了基于器件尺寸大小的热子电路模型和分区域结构的大信号模型缩放规则,建立了完整的大信号缩放模型。与不同栅指数和单位栅宽的GaN HEMT在片测试结果验证表明,该大信号缩放模型能准确地预测基波及高次谐波的负载牵引阻抗特性,以及不同匹配状态下的基波及高次谐波输出功率和效率等特性,并且在大功率高效率功放单片电路(MMIC)中的预测结果精度较高。为大栅宽和高效率功率放大器MMIC设计与优化提供了准确的大信号可缩放模型,同时为大栅宽器件及其模型研究提供了一定的指导作用。
[Abstract]:Gallium nitride (GaN) high electron mobility transistor (HEMT), with its high frequency, high power, high efficiency and so on, has become a hot spot (or nonlinear) characteristic and model of.GaN HEMT, a hot spot in the field of semiconductor devices both at home and abroad in recent years, to optimize the process and structure of the device, guide the circuit design and improve the performance of the circuit. The traditional Si and GaAs based field effect transistor models and their modeling methods are difficult to accurately characterize some special physical properties of GaN HEMT devices, such as traps, heat, harmonic and ambient temperature. Accurate microwave millimeter wave GaN HEMT large signal model is used to improve the performance of devices and shorten the development week of circuits and systems. It is of great significance to improve the rate of finished products, reduce the cost and promote its large-scale system integration and application. With the further reduction of the feature size of GaN HEMT devices, the improvement of the working frequency and output power, and the further demand for the product rate of the circuit design, the research on the modeling of the microwave millimeter wave GaN HEMT is carried out to G The development of aN devices and circuits is of great significance. Therefore, this paper systematically studies the modeling technology of microwave millimeter wave GaN HEMT large signal model based on the mechanism of domestic GaN HEMT technology and the method of empirical based equivalent circuit modeling. The main research contents include: 1. ultra wideband GaN HEMT small signal equivalent circuit model research In view of the parasitism of the microwave millimeter wave GaN HEMT device, on the basis of the traditional transistor small signal equivalent circuit model topology, the gate leakage parasitic resistance Rpgd and the T type parasitic inductance of the gate and the leakage extremes are added. The improved broadband equivalent circuit model structure is established, and the small signal S parameter in the low frequency and the high-end range is improved. On the basis of the direct extraction of model element parameters, a parameter optimization method based on the bias dependent multi-dimensional objective error function is adopted to overcome the shortcomings of the traditional optimization method being trapped in the local minimum and the single bias point to optimize the parameter value without physical meaning. The small signal model is applied to the three kinds. The small signal S parameter prediction results of the same structure GaN HEMT show that the model has good accuracy and universal.2. microwave millimeter wave GaN HEMT large signal electrothermal model in the wide band range of 40 GHz. In view of the nonlinear thermal conductivity of the device material, the nonlinear finite element thermal imitation method is used to establish the nonlinearity of the power as a function. For the asymmetric transconductance of GaN HEMT, based on the traditional Angelov empirical based large signal model, the dependence characteristic of the nonlinear drain current model and the nonlinear gate capacitance model on the grid voltage is improved and modified. The pulse dynamic I-V test technique is used to characterize the trap effect of GaN HEMT, and the inclusion is included. The large signal electrothermal model of heat and trap effect. Compared with the traditional large signal model, the large signal model has higher prediction accuracy for the performance of DC I-V, output power and efficiency. Based on this modeling method, the modeling and large signal output characteristics of different field plate structures are modeled and the large signal output characteristics are analyzed, and the accuracy of the model is further verified. .3. high temperature GaN HEMT large signal thermoelectric model study on high temperature and low temperature HEMT large signal thermoelectric model;.GaN HEMT is often applied to the circuit and system of high and low temperature environment. Its electrical properties are not only influenced by the effect of self heat, but also with the change of ambient temperature. The effect of heat effect and ambient temperature on the GaN HEMT channel temperature is analyzed by using the finite element thermal stability and transient simulation method. The equivalent heat resistance and heat capacity parameters are extracted. The double thermo circuit model with the function of the environment temperature is established. The channel temperature is more accurate at the temperature of -55 to 175 oC. According to the high and low temperature electric heating characteristics, the nonlinear leakage current and the gate capacitance formula are improved. The test and simulation results show that the large signal electric heating model has a high prediction precision of.4.GaN HEM for small signal S parameters, large signal base wave, two harmonic and three harmonic output power and efficiency. T large signal scaling model research. The scalability of large signal model is an important means of modeling large size devices. In view of the thermal coupling effect and complex parasitic characteristics of multi finger devices, this paper takes the medium wide size of the empirical base large signal model as reference, and proposes the physical and geometric characteristics of the gate index and the unit gate width of the GaN HEMT devices. The whole large signal scaling model is established based on the thermo circuit model of the device size and the large signal model of the sub region structure. The GaN HEMT with the different gate index and the unit gate width shows that the large signal scaling model can accurately predict the load traction impedance of the fundamental and high harmonic waves. The accuracy of the prediction results in the high power and high efficiency amplifier monolithic circuit (MMIC) is high. It provides an accurate large signal scalable model for the design and optimization of large grid width and high efficiency power amplifier MMIC. The model research provides a certain guiding role.

【学位授予单位】：电子科技大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN386

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