Electrical Properties of Low-Temperature-Compatible P-Channel Polycrystalline-Silicon TFTs Using High-$\kappa$ Gate Dielectrics
| Autor: | Ming-Jui Yang, Chao-Hsin Chien, Yi-Hsien Lu, Tiao-Yuan Huang, Chih-Yen Shen |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
Negative-bias temperature instability
Materials science Subthreshold conduction business.industry Gate dielectric Transistor Electrical engineering engineering.material Capacitance Electronic Optical and Magnetic Materials law.invention Polycrystalline silicon Thin-film transistor law engineering Optoelectronics Electrical and Electronic Engineering business High-κ dielectric |
| Zdroj: | IEEE Transactions on Electron Devices. 55:1027-1034 |
| ISSN: | 0018-9383 |
| DOI: | 10.1109/ted.2008.916759 |
| Popis: | In this paper, we describe a systematic study of the electrical properties of low-temperature-compatible p-channel polycrystalline-silicon thin-film transistors (poly-Si TFTs) using HfO2 and HfSiOx, high-k gate dielectrics. Because of their larger gate capacitance density, the TFTs containing the high-k gate dielectrics exhibited superior device performance in terms of higher Ion/Ioff current ratios, lower subthreshold swings (SSs), and lower threshold voltages (Vth), relative to conventional deposited-SiO2, albeit with slightly higher OFF-state currents. The TFTs incorporating HfSiOx, as the gate dielectric had ca. 1.73 times the mobility (muFE) relative to that of the deposited-SiO2 TFTs; in contrast, the HfO2 TFTs exhibited inferior mobility. We investigated the mechanism for the mobility degradation in these HfO2 TFTs. The immunity of the HfSiOx, TFTs was better than that of the HfO2 TFTs-in terms of their Vth shift, SS degradation, muFE degradation, and drive current deterioration-against negative bias temperature instability stressing. Thus, we believe that HfSiOx, rather than HfO2, is a potential candidate for use as a gate-dielectric material in future high-performance poly-Si TFTs. |
| Databáze: | OpenAIRE |
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