基於現今移動通信的發展趨勢，高頻與高功率元件愈來愈受矚目，而氮化鎵高電子遷移率電晶體(GaN-based High Electron Mobility Transistor, HEMT)有較高的崩潰電壓與在高功率操作下保有良好的元件特性，成為了高功率元件的重要材料。我們將此氮化鎵元件特性利用ASM-HEMT Model(Advanced Spice Model)進行建模，將元件的物理特性曲線轉換為電腦可讀取模擬的型式，以供後續IC設計者做電路模擬設計使用。
本研究係以ASM-HEMT Model進行氮化鎵元件建模，內容分為直流與小訊號兩部份。ASM-HEMT Model是以半導體物理為基礎的模型，利用表面電荷(surface potential)的計算來模擬出實際元件的特性，故在參數萃取上須同時考慮直流與小訊號兩個部份。文中詳述直流參數的萃取過程，並加入陷補效應(trapping effect)與自發熱效應(self-heating effect)等等非理想因素來使模擬曲線更加吻合元件實際的量測曲線。
本論文亦探討直流特性擬合完成後，小訊號模擬結果卻不準確之情況下，如何改善擬合的步驟與過程，並說明在參數調整時直流與小訊號曲線之間的取捨。

GaN-based high electron mobility transistors (HEMTs) have received increasing attention for 5G mobile communications because of their great potential in millimeter wave high efficiency power amplifiers. In this work, the ASM-HEMT model (Advanced Spice Model) was used to model the device characteristics of an GaN HEMT. The procedures to fit the measured results as well as the effects of fitting parameters on the simulated results are described and discussed in this thesis.
The content of this thesis is divided into two parts, i.e. DC and small signals. The ASM-HEMT model is a physical model constructed based on semiconductor device physics. It uses the surface potential to simulate the characteristics of the device. Therefore, both DC and small signal characteristics must be considered in the parameter extraction processes. In this study, the extraction process of the DC parameters is detailed, and non-ideal effects such as trapping effect and self-heating effect are added to make the simulated results more consistent with the measured results.
This thesis also discusses the iteration fitting procedure to deal with the situation where the small signal simulated results are inconsistent with the measured ones after the DC characteristic fitting process is completed. Detailed illustration of the effect of each parameter and the trade-off between the DC and small signal fitting parameters are also described.

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