In this thesis, we will investigate the mechanism of the degradation on the p-channel Low Temperature Polycrystalline Silicon thin film transistors (LTPS TFTs) under the static and dynamic stresses. The devices are offer by Chi Mei Optoelectronics.
On the static stress, the negative bias temperature instability (NBTI) in the p-channel LTPS TFTs under darkened and illuminated environments was investigated. Experimental results reveal that the generation of Nit showed no change between the different NBTI stresses. However, the generation of Ntrap under illumination was more significant than that in the darkened environment. This phenomenon is mainly caused by the extra number of holes generated during the illuminated NBTI stress.
On the dynamic stress, we found that the degradation of Nit and Ntrap were dependent the stress frequency and the degradation were decreased with the frequency increasing. The results indicated that the mechanism of the degradation was the relation with the response of the major carrier on the poly-Si bulk. In addition, the generation of Ntrap was strongly relation with the rising time of gate-pulse. The Nit revealed no change under the different rising and falling times when gate was applied the dynamic signal. Besides, the generation of Ntrap under illuminated stress was more significant than that in the darkened environment at low stress frequency (<10Hz), but it was no difference at high stress frequency (>10Hz).
Under the mechanical bending, the photosensitive was significantly changed. In n-type TFTs, the quantity of tail state was less in bending condition then in flat condition. The light-induced electrons was trapped by shallow trap and decreasing the photosensitive. However, the phenomenon was no distinct in p-type TFTs. In addition, the generation of the traps and holes in the inversion layer due to mechanical bending was assisted the degradation of the device. The generation of Nit and Ntrap were more serious in bending condition then in flat condition in p-type under the static and the dynamic NBTI stress.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0625109-155237 |
| Date | 25 June 2009 |
| Creators | Hsu, Wei-che |
| Contributors | Tzu-Ming Cheng, Ting-Chang Chang, Cheng-Tung Huang |
| 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-0625109-155237 |
| Rights | campus_withheld, Copyright information available at source archive |
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