以雙離子佈植方式製作應用於無線通訊之平面閘極砷化鎵功率場效電晶體

Abstract

本實驗係以雙離子佈植方式製作應用於無線通訊之平面閘極砷化鎵功率場效電晶體。論文中，我們找尋出最佳的離子佈植條件並得到優良的元件特性。同時，文中亦詳述各個製程步驟的技術，與一些簡單的元件智識。 在論文中我們探討了元件的直流與微波特性。在最佳的離子摻雜條件下，一個0.7 mm × 20 mm尺寸的元件具有250 mA/mm之飽和電流密度、-2.9 V的截止電壓，以及14.9 V的崩潰電壓。該元件在1.9 GHz、3.4 V與400 mA的操作條件下，具有31.73 dBm的最大輸出功率以及 47.52 ﹪的最大功率效益；而其在1.9 GHz、4.7 V與400 mA的操作條件下，具有33.77 dBm的最大輸出功率以及 49.97 ﹪的最大功率效益。此外，在1.9 GHz與4.7 V操作條件下，其ACPR值亦可達到CDMA數位無線通訊系統應用上之要求。 實驗結果顯示此一方式製作之平面閘極砷化鎵功率場效電晶體，在低電壓操作下能提供良好的輸出功率與效益，並具備了不錯的線性度，展現了其在數位通訊上應用的潛力。

The power MESFET by double implantation with a planar-gate has been developed. The doping profile of the ion-implantation was optimized to obtain good device performance. The structure design principles, the device processes and the RF performances of the device developed have been discussed in this thesis as detail as possible. The DC and RF characteristics of the power MESFETs were measured. For the optimal doping profile, the 0.7 mm × 20 mm power MESFET exhibited a saturation current density of 253 mA / mm. The pinch-off voltage and breakdown voltage for the power MESFET were measured as -2.90 V and 14.9 V. At 1.9 GHz operating frequency, the power MESFET supplied 31.73 dBm with maximum efficiency 47.52 % under 3.4 V drain bias and 400 mA quiescent drain current. At 1.9 GHz operating frequency, the power MESFET supplied 33.77 dBm with maximum efficiency 49.97 % under 4.7 V drain bias and 400 mA quiescent drain current. For digital application, under CDMA modulation signal ( at 1.9 GHz ), the ACPR values of the power MESFET was -28.39 / -26.61 dBc ( 1.25 MHz offset ) and -40.94 / -46.25 dBc ( 2.25 MHz offset ) for 3.4 V application and it was with the values of -31.97 / -30.15 dBc ( 1.25 MHz offset ) and -41.07 / -41.49 dBc ( 2.25 MHz offset ) for 4.7 V application. The results showed that the power MESFET device developed using planar-gate technology and double ion-implantation has very good power performance. The device has shown its potential for digital communication applications.