Fabrication and Characterization of Poly-Ge Based Devices
| Autor: | Chang, Yu-Ning, 張佑寧 |
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| Rok vydání: | 2009 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 97 In this study, material properties of poly-Ge thin films and Ni germanides were investigated. The poly-Ge thin films were formed by different crystallization schemes performed on a-Ge deposited by an ultra-high vacuum sputter. From the results of solid-phase crystallization (SPC) method, we found that a-Ge is transformed into poly-Ge at 500 ℃ for 1 hour annealing and then the grain size saturates. For metal-induced crystallization (MIC) method, the crystallization temperature can be reduced with the assistance of Ni and the grain size is bigger than that formed by SPC method. In addition to enhanced crystallization, MIC can be applied to activate dopants at low temperature, termed metal-induced dopant activation (MIDA), because dopants will be rearranged into the substitutional sites during MIC process. Germanide process is expected to reduce the parasitic resistance and alleviate the issue of low dopant solid solubility. We found that the suitable temperature to form NiGe is from 300 ℃ to 375 ℃. Besides, we also fabricate five types of devices in this thesis. From the electrical characteristics, we discovered that poly-Si can increase the crystallinity of poly-Ge and this apparent effect occurs when poly-Si is deposited under the poly-Ge film at the S/D region. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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