| Summary: | 博士 === 中正理工學院 === 國防科學研究所 === 86 === Abstract
A new technique of determining the effective channel length by directly measuring source-drain series resistance of metal-oxide-semiconductor field-effect transistors (MOSFETs) was proposed. By using MOSFETs with scaled gate lengths, the source- drain series resistance can be obtained from a egenerate?device whose source and drain regions are connected. The gate length and the total resistance of the degenerate MOSFET are the lower limits of channel length reduction and source-drain series- resistance, respectively. In order to determine whether a MOSFET source and drain are connected, a quantitative ifference of total resistance?(DTR) method, which can also be used to electrically determine the gate length of a normal MOSFET after the fabrication process, was developed in this study. Also, we proposed qualitative methods to judge whether a MOSFET is degenerate. The effective channel length can then be extracted from the obtained series resistance and I-V of MOSFETs. In this study, the final result of the determined channel length reduction DL is the metallurgical DLmet and the source-drain series resistance is not a constant but clearly showed gate bias dependency. This technique, although requires very short-gate-length devices, is not affected by source-drain series-resistance gate bias dependence issue encountered in conventional I-V methods. Moreover, because of the simplicity of this technique, it can be used in process monitoring, device design and SPICE modeling.
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