高效率微波退火技術應用於非晶態氮摻雜氧化銦鎵鋅薄膜電晶體之研究

Abstract

近年來，非晶態的銦鎵鋅氧化物半導體材料(a-InGaZnO)因具備高載子遷移率及高透光的特性，可用來作為薄膜電晶體的主動層而受到極大的矚目，不過，這類氧化物半導體材料對外界環境較為敏感，在長時間應用上是個待克服的問題。在本研究，在濺鍍過程中直接通入氮氣反應，成功製作出氮摻雜的非晶態氧化銦鎵鋅薄膜電晶體，之後搭配新穎的後退火處理-微波加熱技術，來提升元件的特性。微波加熱技術的優勢在於:對材料有選擇性，快速加熱的製程，降低製程所需時間及熱預算。 和傳統的爐管退火方式比較，經由微波退火處理的氮摻雜氧化銦鎵鋅是較均勻且穩定的薄膜，因此在可靠度量測中臨界電壓偏移量較小，可展現較好的穩定性。因此，微波加熱處理後的氮摻雜非晶態氧化銦鎵鋅薄膜電晶體有潛力發展下一代的大型液晶顯示器(LCDs)和主動式陣列有機發光二極體(AMOLEDs)。

In recent years, amorphous indium gallium zinc oxide (a-IGZO) has attracted substantial attention as candidate materials for the utility in thin film transistors (TFTs) due to their high mobility and light transparent. However, the sensitivity of the oxide-based semiconductor to ambient environment is a critical issue for long-term application. In this work, we successfully deposited the nitrogenated a-IGZO (a-IGZO:N) film by in-sit nitrogen doping during sputtering. In addition, a novel post-annealing method, microwave annealing, is proposed to enhance the a-IGZO:N TFT performance. Microwave annealing technology has the advantages of selectivity to materials, rapid heating process, short process period and low thermal budget. Comparing the microwave annealing method with traditional furnace annealing, a-IGZO:N TFTs have less threshold voltage shift exhibiting better reliability under gate bias stress owing to the less sensitivity against ambient environment and stable thin film quality. Therefore, the microwave annealing technology for a-IGZO:N TFTs thereby has the great potential for next generation large-sized liquid-crystal displays (LCDs) and active matrix organic light-emitting diode displays (AMOLEDs) technology.