考量寄生電阻之氮化鋁鎵/氮化鎵高電子遷移率電晶體 小訊號及大訊號模型

Abstract

隨著4G網路的成熟，以及5G網路無線通訊的開發,其通訊系統中內的功率放大器須具備更好的功率效益，氮化鎵高電子遷移率電晶體能在高功率操作下有好的功率效益，可成為功率放大器的主動元件。通常我們會使用電腦輔助軟體來設計並優化其放大器電路，所以一個能準確預測元件特性的非線性模型就至關重要。在此，本篇研究將針對萃取氮化鋁鎵/氮化鎵高電子遷移率電晶體偏壓情況下的寄生源極及汲極電阻，並進一步說明其小訊號及大訊號模型的建立過程及驗證結果。 在此研究中，吾人採用Curtice Model 建立於砷化鎵由16個集總元件所組成的等效電路結構作為小訊號模型，透過Cold-FET萃取法在特定偏壓下S參數量測而萃取得到外部寄生元件，進一步透過本研究中的牛頓法來萃取與偏壓相關的寄生電阻，最後成功驗證其模型可準確模擬元件的小訊號特性。而大訊號模型則是使用Agilent所發展的ＥＥＨＥＭＴ模型，透過IC-CAP進行一系列量測及參數萃取，並且透過三種不同尺寸元件進行DC-IV以及S參數的驗證，最後再以200um元件驗證其功率特性並得到不錯的結果。

As 4G wireless communication matures, it is crucial that the development of 5G network wireless communications, the power amplifier (PAs) have better power efficiency. Gallium nitride high electron mobility transistor has good power efficiency under high power operation, which can become a good component of power amplifier. We usually use computer-aided software to design and optimize amplifier circuit so a device which can accurately predict the characteristics of non-linear model is essential. In this study, we will focus on the study of parasitic source and drain resistance of the AlGaN/GaN high electron mobility transistor under bias conditions and develop the steps in establishing the small signal and large signal models. In this thesis, we used Curtice model, which was established by GaAs high electron mobility transistor, consisting of 16 lumped elements as our small signal model. From the Cold-FET extraction method, we measured and extracted the extrinsic parameters at a specific bias voltage, and used Newton method to improve the accuracy of parasitic resistances under various bias conditions. Finally, it was verified from the experiment that the model can accurately model the small-signal characteristics of the component. For the large-signal model development, EEHEMT model is used, as developed by Agilent. By a series of measurement and parameter extraction using IC-CAP, we verified DC-IV and S-parameters in the model for three different size devices, and finished the RF power amplifier verification.