在這專題裡，成功的製造出雙 δ-摻雜通道摻雜式異質結構場效電 晶體 (樣本 C)。並且將此元件與其他兩種元件的比較。藉著利用對 稱型通道摻雜式結構所形成的 V 型能帶，我們獲得樣本 C 的一些數 據。它具有很高的閘極偏壓擺幅 1.07 V，線性度 170 mA/mm，崩潰 電壓22 V，導通電壓 1 V，電壓增益 176 mS/mm，還有較低的輸出傳 導值0.9 mS/mm。而樣本 C 與樣本 B 比較，樣本 C 改善了輸出功率 特性與提升熱穩定度。
另一方面，樣本C 改善了通道裡的雜質散射效應，因為它降低了 通道裡的摻雜濃度，而改利用雙 δ-摻雜載子供應層提供大量載子。樣 本C 與樣本 A 能達到高 gm:164 mS/mm、IDS:360mA/mm、fT:17.1GHz，
fmax:34.5GHz 和 NFmin:1.25。
此外，我們研究的雙 δ-摻雜 Al0.3 Ga0.7As/InxGa1-xAs/GaAs 通道摻 雜式異質結構場效電晶體適用於對於線性特性要求很高的元件與高 功率電位應用包括高效率微波功率放大器。
最後，未來在改善元件特性上，有一些問題建議如下：
(1) 為了能夠達到更好的元件特性，在通道與載子供應層裡摻雜 適當的摻雜濃度。
(2) 利用自我對準的 T 型閘極場效電晶體來減少閘極電阻與改 善射頻特性。
(3) 利用 air-bridge 技術來減少側壁效應。
(4) 分析元件的一致性與可靠性。
(5) 試著利用其他的擁有高功函數的合金(如 Ni Ti Pt)，來當蕭基 閘極材料。
參考資料 參考資料 參考資料 參考資料
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