毫米波GaN基HEMT小信号与大信号建模

发布时间：2018-08-05 17:02

【摘要】：本文主要围绕毫米波AlGaN/GaN HEMT等效电路建模工作展开相关研究。在小信号等效电路建模工作中,针对90nm栅长毫米波AlGaN/GaN HEMT建立了相应的小信号等效电路模型,再利用S参数微波测试,成功提取了器件的寄生参数与本征参数。在进一步分析本征参数提取结果后,提出了毫米波AlGaN/GaN HEMT台面边缘电容的概念,并给出了具体的物理模型。为了有效地提取台面边缘电容参数,建立了改进的小信号等效电路模型,再通过分析本征栅电容Cgs、Cgd与栅宽变量的一元线性变化规律,成功提取得到了台面边缘电容参数。另外,为了证实所建立模型的正确性与提取方法的准确性,利用Silvaco器件仿真工具进行了进一步仿真验证,结果显示仿真结果与测试结果吻合良好。通过进一步对台面边缘电容的分析,我们得到以下结论。第一,毫米波器件中的台面边缘电容在总的栅极电容中占有较大的比例,最多可达到33.2%,而这意味着台面边缘电容会对毫米波器件的频率特性产生明显的影响。第二,台面边缘电容在总的栅极电容中所占比例还会随着栅长的减小而不断增大,在20nm超短栅长器件中该比例甚至达到了71.5%左右。因此,消除台面边缘电容是一种可以有效地提升AlGaN/GaN HEMT毫米波器件频率特性的方法。在小信号等效电路建模工作基础上,进一步展开了毫米波AlGaN/GaN HEMT大信号等效电路建模工作。针对毫米波AlGaN/GaN HEMT直流特性,选择利用Curtice立方模型对器件进行直流I-V特性拟合,结合Matlab多元线性回归运算,成功拟合得到相关模型参数。将参数带回Curtice立方模型并与测试结果对比后发现,二者匹配良好。
[Abstract]:This paper focuses on the modeling of millimeter wave AlGaN/GaN HEMT equivalent circuit. In the modeling of small signal equivalent circuit, the corresponding small signal equivalent circuit model is established for 90nm gate millimeter wave AlGaN/GaN HEMT, and the parasitic and intrinsic parameters of the device are extracted successfully by microwave measurement of S parameters. After further analyzing the result of intrinsic parameter extraction, the concept of millimeter-wave AlGaN/GaN HEMT Mesa edge capacitance is proposed, and the physical model is given. In order to extract the parameters of the edge capacitance of the table effectively, an improved small-signal equivalent circuit model is established. By analyzing the linear variation law of the intrinsic gate capacitance Cgsn Cgd and the gate width variable, the parameters of the edge capacitance of the Mesa are extracted successfully. In addition, in order to verify the correctness of the proposed model and the accuracy of the extraction method, further simulation is carried out by using the Silvaco device simulation tool. The results show that the simulation results are in good agreement with the test results. Through the further analysis of the edge capacitance of the table, we get the following conclusions. First, the Mesa edge capacitance in millimeter wave devices accounts for a large proportion of the total gate capacitance, up to 33.2um, which means that the Mesa edge capacitance will have an obvious effect on the frequency characteristics of millimeter-wave devices. Secondly, the proportion of the edge capacitance in the total gate capacitance will increase with the decrease of gate length, and the proportion of the gate capacitance in 20nm ultra-short gate length devices can reach about 71.5%. Therefore, eliminating the edge capacitance is an effective method to improve the frequency characteristics of AlGaN/GaN HEMT millimeter wave devices. Based on the modeling of small signal equivalent circuit, the modeling of millimeter wave AlGaN/GaN HEMT large signal equivalent circuit is further developed. According to the DC characteristics of millimeter-wave AlGaN/GaN HEMT, the DC I-V characteristic of the device is fitted with the Curtice cubic model, and the parameters of the model are obtained successfully by combining the multivariate linear regression operation with Matlab. The parameters are brought back to the Curtice cubic model and compared with the test results. It is found that the two parameters match well.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN386

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