本研究藉由電子束微影製程技術搭配光電化學法完成製作多重通道及多重T型閘極氮化鋁鎵/氮化鎵高電子遷移率場效電晶體，80 nm寬之多重通道結構利用電子束微影系統曝寫圖形與光電化學濕式蝕刻法蝕刻而形成；另一方面，在多重T型閘極的部份，同樣以電子束微影系統曝寫多重T閘極圖形之底部(線寬為80 nm)，再利用黃光微影定義閘極區域及後續製程，完成多重T型閘極結構。
本研究比較光電化學法生長、氧化鋁及二氧化矽之閘極氧化層於不同結構下的特性，其結構分為平面式單閘極、多重通道結構、多重通道及多重閘極結構與多重通道及多重T型閘極結構。光電化學法生長、氧化鋁及二氧化矽之閘極氧化層於平面式單閘極結構下，汲源極電壓(VDS)為10 V和閘源極電壓(VGS)為5 V下，汲源極飽和電流(IDSS)分別為490 mA/mm、480 mA/mm及475 mA/mm，在汲源極電壓為10 V時，最大轉移電導值(gm(max))分別為90 mS/mm、88 mS/mm及80 mS/mm，次臨界擺幅(subthreshold swing, S.S.)分別為368.3 mV/dec、374.6 mV/dec及390.1 mV/dec。
進一步比較光電化學法生長、氧化鋁及二氧化矽之閘極氧化層於多重通道結構下，汲源極電壓(VDS)分別操作於3 V、3.5 V及4 V且閘源極電壓(VGS)為5 V下，汲源極飽和電流(IDSS)分別為1153 mA/mm、1131 mA/mm及929 mA/mm，最大轉移電導值(gm(max))分別為265 mS/mm、240 mS/mm及223 mS/mm，次臨界擺幅(subthreshold swing, S.S.)下降至100.1 mV/dec、105.3 mV/dec及118.1 mV/dec，截止頻率(cut-off frequency, fT)分別為7.7 GHz、7.4 GHz及6.9 GHz，而最大震盪頻率(maximum oscil-lation frequency, fMax)分別為15.1 GHz、14.2 GHz及13.7 GHz。
再進一步比較光電化學法生長、氧化鋁及二氧化矽之閘極氧化層於多重通道及多重閘極結構下，汲源極電壓(VDS)分別操作於3 V、3 V及4 V且閘源極電壓(VGS)為5 V，汲源極飽和電流(IDSS)分別為1958 mA/mm、1949 mA/mm及1795 mA/mm，最大轉移電導值(gm(max))分別為323 mS/mm、321.5 mS/mm及309 mS/mm，次臨界擺幅(subthreshold swing, S.S.)下降至95.5 mV/dec、98.8 mV/dec及107.1 mV/dec，截止頻率(cut-off frequency, fT)分別為12 GHz、10.8 GHz及8.9 GHz，而最大震盪頻率(maximum oscillation frequency, fMax)分別為18.6 GHz、16.9 GHz及15.8 GHz。
最後將多重閘極改為T型閘極結構，通道的部份維持多重通道結構，閘極氧化層為光電化學法生長、氧化鋁及二氧化矽之氧化層進行比較，汲源極電壓(VDS)分別操作於3 V、3 V及3.5 V且閘源極電壓(VGS)為5 V，汲源極飽和電流(IDSS)分別為2009 mA/mm、1996 mA/mm及1821 mA/mm，最大轉移電導值(gm(max))分別為340 mS/mm、333 mS/mm及318 mS/mm，次臨界擺幅(subthreshold swing, S.S.)下降至98.5 mV/dec、86.2 mV/dec及82.2 mV/dec，截止頻率(cut-off frequency, fT)分別為12.8 GHz、11.6 GHz及10.7 GHz，而最大震盪頻率(maximum oscillation frequency, fMax)分別為30.9 GHz、30.2 GHz及29 GHz，當使用光電化學氧化法生長閘極氧化層的同時，也有效形成閘極掘入結構，此結構能夠縮減二維電子氣通道與閘極間之距離，能夠更有效地控制二維電子氣密度，將進一步提升閘極控制力，並使漏電流減少，加快元件切換速度。

In this research, multi-channel and multiple T-gate structured AlGaN/GaN metal- oxide-semiconductor high-electron-mobility transistors were fabricated by using electron beam lithography system and photoelectrochemical method. The electron beam lithography system could fabricate thinner nanowire than the conventional exposure machine.
It is worth mentioning that we used photoelectrochemical wet oxidation method to grow high quality gate oxide on the AlGaN surface directly, it also could avoid AlGaN surface damage by plasma. The multiple T-gate structure was fabricated by using electron beam lithography system and combining Photolithography system. Combine the above structures and advantages, we successfully fabricated the multi-channel and multiple T-gate structured metal-oxide-semiconductor high-electron-mobility transistors with different gate oxide layers. Multi-channel structure could increase the area between gate and channel to enhance the gate control capability, and T-gate structure could reduce the gate resistance and improve the high frequency characteristics.
The saturation drain–source currents (IDSS) at VDS = 3 V and VGS = 5 V of the multi-channel and multiple T-gate structured MOS-HEMTs were 2009 mA/mm, the maximum transconductance (gm (max)) were 340 mS/mm, the cut-off frequency and the maximum oscillation frequency were 12.8 GHz and 30.9 GHz, respectively.

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