Fabrication and Characterization of GaN MESFETs 黃佳鴻、蕭宏彬
E-mail: [email protected]
ABSTRACT
As GaN material shows very good optoelectronic properties, it has been widely used in the application of light emitting devices, such as blue and green light emitter diodes (LED). Also, GaN with large energy bandgap is very suitable for the fabrication of the high power electronic devices, such as FETs and HBTs. The most important requirement for the fabrication of high quality FETs is that the gate leakage current should be as low as possible. Based on the conventional experience, the gate structure might be MOS, MIS, or Schottky contact. In this work, the GaN layer structures for the fabrication of MESFETs were grown on sapphire substrates by metal-organic chemical vapor deposition (MOCVD). We adopted an alloy of Ti/Al for the formation of ohmic contact on both drain and source terminals. An alloy of Ni was used for the Schottky contact on the gate terminal. Finally, the processed FET devices were measured and the characteristics of I-V curves would be analyzed and discussed.
Keywords : GaN ; MESFET ; Schottky contact
Table of Contents
第一章 序論 1.1 研究動機．．．．．．．．．．．．．．．．．．1 1.2 氮化鎵特性．．．．．．．．．．．．．．．．
．2 1.3 論文架構．．．．．．．．．．．．．．．．．．4 第二章 金半場效電晶體理論基礎．．．．．．．．．．．．
．5 2.1 環型傳輸線模型．．．．．．．．．．．．．．．5 2.2 蕭特基接面．．．．．．．．．．．．．．．．8 2.3 接面 場效電晶體觀念．．．．．．．．．．．．12 第三章 元件製作．．．．．．．．．．．．．．．．．．．．14 3.1 元件隔 離(mesa isolation)製作．．．．．．．16 3.2 歐姆接觸(ohmic contact)電極製作．．．．．．19 3.3 閘極製作．．．．．．．
．．．．．．．．．．21 第四章 元件電性量測結果與討論．．．．．．．．．．．．．23 4.1 霍爾量測．．．．．．．．
．．．．．．．．．．23 4.2 歐姆量測．．．．．．．．．．．．．．．．．24 4.3 蕭特基接觸量測．．．．．．．．．
．．．．．．25 4.4 電性量測．．．．．．．．．．．．．．．．．．28 第五章 結論．．．．．．．．．．．．．．．．
．．．．．．31 附錄一．．．．．．．．．．．．．．．．．．．．．．．．．32 參考文獻．．．．．．．．．．．．
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