Stability of polysilicon thin film transistors under switch operating
| Autor: | Tayeb Mohammed-Brahim, Jean-François Llibre, Olivier Bonnaud, K. Mourgues, F. Raoult, Y. Helen, H. Toutah, Boubekeur Tala-Ighil |
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| Rok vydání: | 2000 |
| Předmět: |
Materials science
business.industry Electrical engineering Field effect Chemical vapor deposition Condensed Matter Physics Subthreshold slope Atomic and Molecular Physics and Optics Surfaces Coatings and Films Electronic Optical and Magnetic Materials Active layer Amorphous solid Threshold voltage Switching time Thin-film transistor Optoelectronics Electrical and Electronic Engineering Safety Risk Reliability and Quality business |
| Zdroj: | Scopus-Elsevier |
| ISSN: | 0026-2714 |
| DOI: | 10.1016/s0026-2714(00)00174-8 |
| Popis: | Ageing of low temperature polysilicon Thin Film Transistors (TFTs) under AC gate bias stress is reported in this study. The active layer of these high performances transistors is amorphous deposited using Low Pressure Chemical Vapor Deposition (LPCVD) technique. The drain and source regions are in-situ doped during the LPCVD deposition by using phosphine to fabricate n-type transistors. The active layer and the drain arid source regions are Solid Phase Crystallized. The field effect mobility is higher than 100 cm2/V.s, the subthreshold slope around 0.6 V/dec, the threshold voltage around 0.2V and the switching time around 370 nsec. As these TFTs are commonly used as switching devices in the most of applications in large area electronics field, the study of their stability under AC electrical stress is important. The present work shows that the effect of the positive or negative DC stress is higher than that of the AC stress and then the degradation of polysilicon TFTs is over-estimated when it is checked from the effects of DC gate bias stress. Degradation under bias stress is shown to originate from the creation of gap states at the channel-interface oxide and in the channel material. The lower influence of the AC stress is explained from an annealing effect of the created states by the application of an opposite sign bias stress. |
| Databáze: | OpenAIRE |
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