GaN基电子器件小信号等效电路参数提取与分析

发布时间：2018-03-07 07:05

本文选题：微波半导体　切入点：AlGaN/AlN/GaN　出处：《山东大学》2015年硕士论文　论文类型：学位论文

【摘要】：近年来,由于微波技术的不断发展,微波半导体器件已经在无线通信、遥测系统、导航以及军事领域取得了广泛的应用。GaN作为第三代半导体材料的代表,因其具有宽的禁带宽度、高的击穿电场、高的热导率、高的电子饱和漂移速度、高的热导率及高的抗辐射能力,所以在射频、微波和毫米波等高频以及大功率器件领域中得到广泛应用。目前对GaN基电子器件和电路虽然已经进入了应用阶段,但是电路设计中GaN基HMETs器件模型多沿用GaAs的模型,如Angelov模型、TriQuint模型等。因此建立精确的GaN HMETs等效电路模型对于电路设计、器件性能提升,特别是对器件的大信号建模有着十分重要的指导意义。本文正是以这些问题为出发点,在以下方面进行了具体的研究：1、研究了一种新的方法对AlGaN/AlN/GaN异质结场效应晶体管小信号等效电路进行参数提取。根据制得的器件的特性,采用了16元件模型。对于寄生电感和寄生电容的提取采取了射频去嵌入技术。而对于小信号参数模型中最为重要且最难提取的寄生电阻部分,利用公式推导出Re(Z12)与Rs的关系,通过迭代计算求解Rs,在得到Rs后可计算出Rd,避免了以往寄生电阻不随器件偏置点变化而变化的弊端,且经过对比传统方法,新方法的拟合效果更令人满意。2、研究了AlGaN/AlN/GaN异质结场效应晶体管截止频率fT与器件尺寸的关系,进而分析了影响fT的主要参数是gm与栅电容。又研究了器件本征参数变化规律,发现本征跨导gm随频率的升高呈现下降的趋势,其原因可归结于低频时栅源、栅漏之间的表面漏电流区也被调制,这样会增大跨导,当频率升高时,表面陷阱态中的电子来不及响应外加信号的变化,使得跨导降低。3、研究了AlGaN/AlN/GaN异质结场效应晶体管电流崩塌效应,通过对器件进行栅极电压脉冲测试对比直流的测试结果,发现很明显的电流崩塌效应,同时发现对于不同的栅极脉冲宽度,脉冲宽度越小,器件电流崩塌程度越明显,由于测试器件未做钝化,结合“虚栅”模型分析了电流崩塌效应与器件表面态间的关系。
[Abstract]:In recent years, due to the rapid development of microwave technology, microwave semiconductor devices have been in a wireless communication system, remote sensing, navigation and military fields has been widely used.GaN as a representative of the third generation of semiconductor materials, because of its wide band gap, high breakdown field, high thermal conductivity, high saturated electron drift velocity. High thermal conductivity and high resistance to radiation, so widely used in RF, microwave and millimeter wave high frequency and high power devices in the field. The GaN based electronic devices and circuits have been entered into the application stage, but the circuit design of GaN based HMETs model using GaAs model, Angelov model TriQuint, model and so on. So the establishment of GaN HMETs equivalent circuit model for accurate circuit design, device performance, especially it is very important to large signal modeling of the device. This paper is based on these issues as a starting point, the specific research in the following aspects: 1, research on a new method for parameter extraction of junction field effect transistor small signal equivalent circuit of AlGaN/AlN/GaN. According to the characteristics of heterogeneous devices prepared, using the 16 element model. For the extraction of parasitic inductance and parasitic capacitance take the RF de embedding technique. For small signal parameters in the model is the most important and the most difficult part of the parasitic resistance extraction, using the formula Re (Z12) and Rs, through iterative calculation for Rs, in Rs can be calculated Rd, to avoid the disadvantages of the parasitic resistance with the device the bias point changes, and after comparing with the traditional method, the fitting effect of the new method is much more satisfactory.2, the relationship between AlGaN/AlN/GaN heterostructure field effect transistor size cutoff frequency fT and the device, and analyzes the Influence of the main parameters of fT is GM and the gate capacitor. Study the intrinsic variation of parameters of the device, found the intrinsic transconductance of GM with the increase of the frequency decreased, it can be attributed to the low surface leakage between gate and source, gate leakage current region is modulated, which increases the cross guide, when when the frequency increases, the electron surface trap states have not enough time to respond the external signal changes, the transconductance decreased.3, the AlGaN/AlN/GaN heterojunction field effect transistor current collapse effect, the test results of gate voltage on the DC pulse contrast test device, found that the current collapse effect obviously, at the same time for different gate the pulse width, the pulse width is smaller, the device current collapse degree is obvious, because the test devices do not passivation, analyzes the relationship between the current collapse effect and device surface state combination between "virtual gate" model.

【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN386

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