隨著無線網路科技的日新月異，射頻功率放大器已經被不斷的研究與改進數十年。但是傳統矽製程橫向射頻高功率金氧半場效電晶體因為崩潰電壓過低無法提供較高的功率密度，所以寬能帶半導體材料便成了應用於射頻元件的新選擇，碳化矽因為材料優勢例如寬能帶、高崩潰電場、高飽和電子速度及高熱傳導係數因此非常適合用在高頻高功率上的應用。
在本論文中，我們專注在半絕緣基板上設計和製作射頻功率金氧半場效電晶體，包含使用電子束顯影系統製作出小於1μm的閘極長度、低片電阻源極和汲極離子佈值及活化和無燒結金屬接點。採用磷佈值源極和汲極可得到片電阻207.5(Ω/square)及無燒結金屬可得到接觸電阻2.4x10-5(Ωcm2)，並且遷移率可得到63(cm2/Vs).我們也觀察使用低溫氧化介電層製程製作金氧半場效電晶體是否可以改善通道遷移率，並且設計和製作出不同結構射頻金氧半電晶體如掩埋通道避免過低的通道遷離率、輕摻雜漂移區域以增加操作電壓。

In this thesis, we focus on the design and process of 4H-SiC RF MOSFETs on a semi-insulating substrate, including e-beam lithography for submicron gate length, low sheet resistance source/drain implantation and activation, and non-annealed ohmic contact. The observed sheet resistance in the phosphorus implanted Source/Drain is 207.5 (Ω/square). Non-annealed contact resistance is 2.4x10-5(Ωcm2).The achieved mobility of no contact annealing MOSFET is 63 cm2/Vs.
The fabrication sequences of the 4H-SiC RF MOSFETs on semi-insulating substrate with different device structures such as buried channel to avoid low surface mobility, and lightly doped drift region to increase operating voltage is demonstrated.

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