Browsing by Author "Chang, Tai-Yuan"

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Effects of low-temperature Si buffer thickness and SiGe oxidation on sensitivity of Si1-xGex nanowire
(2015-06-01)
Lai, Yi-Lung
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Chang, Tai-Yuan
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Chang, Kow-Ming
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Chen, Chu-Feng
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Lai, Chiung-Hui
Si1-xGex nanowire biosensors are attractive for their high sensitivity due to the large surface-to-volume ratio, high carrier mobility, and silicon compatibility. In this work, we study the effect of the thickness of the low-temperature Si (LT-Si) buffer layer on an insulator on the sensitivity of oxidized Si1-xGex nanowire samples with different Ge contents by increasing the Si buffer thickness from 20 to 60 nm. 3-Aminopropyltrimethoxy-silane (APTMS) was used as a biochemical reagent. It was demonstrated that, with the proper Ge content and LT-Si buffer thickness, the sensitivity of the Si1-xGex nanowire is high and it can be further improved by Si1-xGex oxidation. This can be attributed to the reduction of the diameter to the nanometer order, which gives rise to an increased surface-to-volume ratio and further enhances the sensitivity of the biosensor. (C) 2015 The Japan Society of Applied Physics
Electrical properties of SiGe nanowire following fluorine/nitrogen plasma treatment
(2014-01-15)
Chang, Kow-Ming
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Chen, Chu-Feng
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Lai, Chiung-Hui
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Kuo, Po-Shen
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Chen, Yi-Ming
The improvements to electrical properties of SiGe nanowires by surface plasma treatment were investigated. Various durations of pre-oxidation with fluorine; ambients for post-nitridation plasma treatment, and annealing temperature after plasma treatment, 800-950 degrees C, were applied. Pre-oxidation treatment using fluorine plasma; improved the conductance of SiGe nanowires because the Si-F binding energy created a more stable interface state than bare nanowire on the surface of SiGe. N-2 plasma incorporated more N than does in NH3 plasma, and NH3 has the drawback of introducing electron traps, causing Si-H bonds to break in the subsequent annealing process. Since the reparation of surface defects by plasma treatment is valid, the high post-annealing temperature to reduce defect by re-crystallizing can be reduced. Hence, Ge diffusion at low post-annealing temperature did not reduce the high concentration of Ge at the SiGe nanowire surfaces. (C) 2013 Elsevier B.V. All rights reserved.
Influence of Surface State on Biochemical Sensing Using SiGe Nanowire
(2015-06-01)
Lai, Chiung-Hui
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Chang, Kow-Ming
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Chen, Yi-Ming
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Chen, Chu-Feng
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Kuo, Po-Shen
Nanowires are extensively used to fabricate highly sensitive electrical sensors for detection of biological and chemical species. The hole mobility can be promoted by the increasing Ge fraction in SiGe, achieved by the oxidation-induced Ge condensation. However, oxidation increases the number of surface states, which brings the nonnegligible contribution in mobility degradation. In this work, 3-aminopropyltrimethoxysilane (APTMS) was used as a biochemical reagent to modify the surface of SiGe nanowires, then bonding to bio-linker, bis (3-sulfo-N-hydroxysuccinimide ester) sodium salt (BS3). Various methods have been proposed for increasing sensitivity of boron-doped SiGe nanowires, such as capping layer, surface treatment, and annealing temperature.
Investigation of Defect Free SiGe Nanowire Biosensor Modified by Dual Plasma Technology
(2016-02)
Chen, Yi-Ming
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Chang, Tai-Yuan
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Lai, Chiung-Hui
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Chang, Kow-Ming
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Chen, Chu-Feng
Semiconductor nanowires (NWs) have been extensively investigated and discussed in various fields due to their unique physical properties. In this paper, we successfully produce SiGe NWs biosensor by VLSI technology. We propose the dual plasma technology with CF4 plasma pre-treatment and N-2 plasma post-treatment for repairs of defects as well as optimization of SiGe NWs biosensor. The results indicate that sensitivity (S) of the biosensor with dual plasma technology has significantly improved at least 32.8%, suitable for producing industrial SiGe NWs biosensor in the future.