藉由有機保護層提升a-IGZO 薄膜電晶體之穩定性及可靠度之探討

Abstract

在本篇論文當中，我們成功地藉由射頻濺鍍(RF sputter)的方式製造a-IGZO薄膜電晶體，並使用了有機的保護層(passivation layer)來探討其對於a-IGZO薄膜電晶體的可靠度提升的效能與程度。實驗中進行兩種有機材料，FH6400 and Durimide 115A，的評估與量測分析。 從實驗數據可以看到，有了有機保護層之a-IGZO薄膜電晶體，在不會讓基本電性劣化的同時，能夠將hump現象摒除，並將遲滯的量從沒有有機保護層保護之元件的0.3伏特降低到0.1及0.05伏特。此外，在升溫條件下，元件在多了有機保護層之後，也能有比較好的穩定性，即使在150℃的高溫條件下，有了Durimide 115A保護之薄膜電晶體的次臨界擺幅數值為256 mV/decade，就能遠小於沒有有機保護層之元件的518 mV/decade，且有了有機保護層保護的元件，甚至在放置三個月後，還沒有很顯著的電性劣化。 而在偏壓施加或照紫外波段光源等條件之下，因為能夠有效地阻隔周遭氣體擴散進入a-IGZO通道層，因此有了有機保護層保護之a-IGZO薄膜電晶體，也能夠有效地提升其穩定性。

In this thesis, a-IGZO TFTs were fabricated by RF sputter successfully. Nevertheless, the a-IGZO material is sensitive to the surrounding ambient, so we explore the effectiveness of applying organic materials as the passivation layers in improving the stability of the devices. Two types of organic materials, FH6400 and Durimide 115A, were explored in this study. With the capping of organic passivation layers, passivated a-IGZO TFTs can eliminate the hump phenomenon effectively and would not introduce undesirable side effects. Moreover, the 0.3(V) hysteresis window of unpassivated devices are reduced to 0.1(V) and 0.05(V) for organic-passivated splits. In addition, with the Durimide 115A passivation layer, the subthreshold swing value of passivated devices is 256 mV/decade, much smaller compared to the 518 mV/decade of unpassivated devices. Devices with organic passivation layers also exhibit more stable performance even exposed to atmosphere for three months. Due to the effective prevention of the diffusion of the gas molecules to the channel layers, organic-passivated devices have better stability under illumination with or without bias stress.