有機與氧化物薄膜電晶體於前瞻顯示器應用之研究

Abstract

本論文研究有機與氧化物薄膜電晶體。 論文前半部是研究以有機半導體五環素(pentacene)為主動層的薄膜電晶體。傳統有機薄膜電晶體 (OTFTs) 存在許多缺點，如過高的操作電壓，對光敏感及可靠度不佳等等因素。本研究提出使用高介電常數有機無機複合介電層來降低因載子遷移率過低造成的高操作電壓，並利用有機無機複合介電層中的奈米粉體做為電子電洞復合中心降低有機薄膜電晶體的光敏感度。此外，本研究率先使用一些功能性的有機介電層製作出含有彩色濾光片功能的薄膜電晶體，此研究展示了有機電子的多種功能性。後半段是研究非晶銦鎵錫氧化物(amorphous In-Ga-Zn-O)薄膜電晶體 (a-IGZO TFTs)。 a-IGZO的載子遷移率快(約10~60 cm2/Vs)，為一種可能取代非晶矽薄膜電晶體的新材料。本研究先對a-IGZO的材料特性如光學特性、導電度跟溫度的關係做探討，之後對a-IGZO TFT在不同波長光的照射下的電性表現做深入的研究，並在最後提出一個具有物理含意的電性參數模型，作為日後發展可透視性電路或高速電路應用的基礎。 最後並成功結合pentacene/a-IGZO兩種半導體材料製作成雙極性薄膜電晶體(ambipolar TFTs)，製作成CMOS-like inverter circuit可應用並簡化顯示器上之驅動電路。

This dissertation is divided into two parts. In the first part, it focuses on the pentacene-based organic thin-film transistors (OTFTs). There are many issues of traditional OTFTs, such as high operating voltage, photosensitivity, and poor reliability. We proposed that using high □ organic-inorganic nanocomposite dielectric as gate insulator to reduce the operating voltage caused from low material mobility. Furthermore, we used nanoparticles of composite dielectric as recombination centers to reduce photosensitivity of pentacene-based OTFTs. In addition, we also integrated color filter into TFT array. This study demonstrated one potential example for multifunctional organic electronics. The second part discusses the properties of amorphous In-Ga-Zn-O thin-film transistors (a-IGZO TFTs). We first studied the optical, thermal, and electrical properties of a-IGZO film. Next, the electrical properties under different wavelength illumination of a-IGZO TFTs were studied. Furthermore, the a-IGZO density of states, simulation and modeling were investigated for the visible and high-speed electronics applications. Finally, we successfully combined pentacene and a-IGZO as active layer to make ambipolar TFTs. These devices show both p-type and n-type characteristic. CMOS-like inverter circuit was made to demonstrate the possibility for display applications.