氮化鎵材料本身具有高電子飽和速度、高臨界電場及低導通電阻的特性，使氮化鎵製程所做出的功率元件具有較傳統矽製程好的特性，但其效能仍然會受元件本身的熱效應和元件參數所限制。由於改善元件本身的熱效應會讓元件的特性大幅提升，因此本論文參考了過去一些研究方法，並在現實條件可行的前提下，構想出將元件特性優化的做法。將這些方法應用到晶片後，除了進行較傳統的脈衝(Pulse)量測和負載推移(Load-pull)量測作為分析之用，也引進近年來較為新興的X參數(X-parameter)作為另一個研究的重點。
本論文將會著重於利用氮化鎵製程的電晶體特性優化以及高電子遷移率電晶體(HEMT)的X參數研究。首先，在第一章當中會提出本論文的研究背景及動機，並且將說明整篇論文的大致架構。第二章會從氮化鎵的材料特性開始介紹，進而提及高電子遷移率電晶體的操作特性。在第三章中，依序介紹本論文中三種主要的量測及分析方法，包含脈衝量測和負載推移量測以及X參數量測。第四章中，會參考其他文獻，提出優化高電子遷移率電晶體特性的做法，並實際應用於晶片製作上。待晶片製作完成後，進行第三章中所提及的三種量測及分析，比較應用此做法的前後差異與優劣，並分析其量測結果。最後，在第五章中，將統整上述的研究內容並提出未來可能的發展方向。期望從電子元件的特性，進而至電路設計上的效能都能獲得改善。更甚者，能對半導體產業上產生小小的助益，為社會盡一份心力。

GaN presents the property of high electronic mobility, high critical electric and low turn on voltage, which make it a better power device material than silicon. However, the performance of the device is restricted by heating effects and the device parameters. Therefore, some researches worked on improving the device performance by changing the device structure. This thesis mainly focuses on GaN HEMT, taking some of the previous researches as reference, and combines with practical methods to design and improve the device performance. In addition, it presents three measurement methods to characterization the devices: pulse I-V, load-pull, and X-parameter measurement.
In chapter 2, the GaN material properties are introduced, followed by the basic GaN HEMT properties. In chapter 3, the three measurement methods for characterizing the devices are presented, including pulse I-V, load-pull, and X-parameter measurement. In chapter 4, a new method to improve the device performance would be introduced. With the new method applied to process technology, the chips can be measured by the three measurements introduced in chapter 3. Finally, the conclusion of the thesis would be made in chapter 5, along with some possible directions of further research.

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