Characterization of Ohmic Contact Yttebium Germanide Formed Using Microwave Annealing
| Autor: | Sheng-Hao Chen, 陳聖浩 |
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| Rok vydání: | 2014 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 103 Because of the innate characteristic of germanium, the Fermi level pinning effect causes the work function of all kind of metal germanide are fixed close to the edge of valance band, unlike silicide. Therefore, the study of unpinning metal germanide is challenging. Ytterbium is the most potential material in lanthanoids due to its lower work function. For this reason, it would get the lower Schottky barrier height (SBH) on the contact of S/D for n-MOSFETs. It will enhance the driving current. In this study, we use two methods, Microwave Annealing (MWA) and Rapid Thermal Annealing (RTA), to form Ytterbium Germanide (YbGe). There are two parts in our experiment – the material analysis and the electrical measurement. In the material analysis, we use Four-Point-Prober, X-Ray Diffraction (XRD), Transmission electron microscopy (TEM), and Energy Dispersive X-ray Analyzer (EDS) to verify the sheet resistance, the intensity of crystallization, the thickness of Ytterbium germanide, and percentage of elements. According to the results, we selected the appropriate annealing temperature to form the YbGe for the diode fabrication. In electrical measurement, based on the I-V curves of YbGe diodes, we suggested the results which are helpful to enhance the driving current on n-MOSFET. Besides, we measured the I-V curve of YbGe/Ge diodes at different temperatures for calculating SBH. This verifies the driving current whose YbGe is higher than other metal germanide for n-MOSFET. The results of material analysis imply MWA is advantaged on forming YbGe rather than RTA due to low temperature process. However, the results of electrical measurements, no matter RTA or MWA, were still ohmic contact for YbGe/p-Ge. But, the result is different for YbGe/n-Ge. The lower process temperature forming YbGe is closer to ohmic contact. Conversely, the higher temperature is closer to Schottky contact. Key word: Schottky barrier height, Microwave Annealing, Ytterbium Germanide, Diode, Ohmic contact. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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