Browsing by Author "Lin, Tzung Han"

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Enhancement of detection by selective modification of silicon nanobelt field-effect transistors via localized Joule heating
(2014-03-01)
Liu, Hao Heng
;
Lin, Tzung Han
;
Sheu, Jeng-Tzong
;
材料科學與工程學系奈米科技碩博班
;
Graduate Program of Nanotechnology , Department of Materials Science and Engineering
We utilized localized Joule heating to ablate methoxy-poly (ethylene-glycol)-silane (mPEG-sil) modified on the p(-) region of an n(+)-p(-)-n(+) silicon nanobelt field-effect transistor (SNFET). SNFETs with selective modifications of 3-aminopropyltrimethoxysilane (APTMS) and NHS-biotin on the ablated region exhibited a faster sensing response rate and a higher sensitivity in real-time detection of Streptavidin (SA). Characterization of the ablated region via lateral force microscopy and the fluorescence image show that the ablation region occurs only in the p(-) region near the drain side and is believed to be a result of the impact ionization mechanism during Joule heating. Moreover, a bias of 20 V pulse voltage for 1 ms successfully ablates mPEG-sil and reduces the device off leakage current by 1 order after Joule heating. However, Joule heating with a pulse voltage larger than 20V (1 ms) yielded an increase of device off leakage owing to damage to gate dielectrics during Joule heating. A comparison of real-time detection of SA between selectively and non-selectively modified chips shows that selectively modified ones exhibit a better limit of detection (LOD) that is one order lower than non-selectively modified ones, and a sensing response rate twice as fast as the non-selectively modified one for every target concentration. (C) 2013 Elsevier B.V. All rights reserved.
Self-Assembled Monolayer-Based Selective Modification on Polysilicon Nanobelt Devices
(2013-10-01)
Liu, Hao Heng
;
Lin, Tzung Han
;
Sheu, Jeng-Tzong
;
材料科學與工程學系
;
Department of Materials Science and Engineering
In this study, a self-assembled monolayer (SAM) of methoxy-poly (ethylene-glycol)-silane (mPEG-sil) was used to modify the silicon dioxide surface of polysilicon nanodevices (PNDs) to act as a passivation layer that inhibits nonspecific binding of proteins and reduces localized Joule heating power. Selective modifications of 3-aminopropyltrimethoxysilane (APTMS), NHS-biotin and dye-labeled Streptavidin on the removal regions were characterized. These PNDs, which consist of a two-level doping profile, were designed to confine heat in the low-level doping region during localized Joule heating. Localized Joule heating with pulse bias was examined in both vacuum and ambient, which indicated the removal region was longer in vacuum for the same pulse bias. Moreover, a comparison of selectively and nonselectively modified PNDs observed in time-lapsed fluorescence detection of dye-labeled Streptavidin showed a higher increasing rate in fluorescence intensity (similar to 2x enhancement) in the selectively modified PNDs. Finally, a COMSOL simulation was employed to evaluate the temperature distribution in the PNDs, with results showing that heat confinement was observed in the low-level doping region and a temperature very close to 673 K was achieved while applying a pulse voltage (40 V, 5 mu s) to remove mPEG-sil.