In recent years, amorphous oxide semiconductors have been studied due to their superior characteristics, such as transparent property, high electron mobility exceeding 10 cm2/V¡Es, and can be fabricated on plastic substrates at low temperatures. According to these advantages, a-IGZO thin-film transistors are promising as next-generation electronic devices.
Although a-IGZO TFTs have such unique properties, the electrical performances are strongly dependent on its environment such as oxygen, water and visible light. In this study, the electrical characteristics of a-IGZO TFTs under positive bias stress with different ambient gases have been discussed. In particular, the total duration of the negative gate bias applied on the switching transistor is larger than that of the positive gate bias in display application. Therefore, the electrical stability under negative bias stress is vital to investigate. Moreover, a-IGZO TFT regarded as a panel switch may be exposed to visible light for the application of liquid crystal display. The electrical stability under illumination of visible light is also important to study.
Experiment results show that device characteristics are affected under water-containing oxygen ambience. We indicates that the existence of water molecules can assist more oxygen to adsorb on the a-IGZO surface than the case without water assisting. That cause the variation of transfer curve under positive bias stress. However, the degradations in subthreshold swing and threshold voltage are caused by the state-related adsorption of water molecules under negative bias stress. Furthermore, adsorbed oxygen on the surface of a-IGZO can be desorbed by illumination of visible light, leading to large variation in transfer curve.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0719111-122309 |
| Date | 19 July 2011 |
| Creators | Chen, Yi-Hsien |
| Contributors | Tsung-Ming Tsai, Cheng-Tung Huang, Osbert Cheng, Ting-Chang Chang, Ann-Kuo Chu |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0719111-122309 |
| Rights | restricted, Copyright information available at source archive |
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