Browsing by Author "Hsieh, Cheng-Ting"

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EFFECT OF THE MIXED N-2/O-2 OXIDATION PROCESS ON IMPROVEMENT OF THE SENSITIVITY OF THE SIGE NANO-WIRE
(2011-01-01)
Chang, Kow-Ming
;
Chen, Chu-Feng
;
Lai, Chiung-Hui
;
Wang, Yu-Bin
;
Liu, Chung-Hsien
Ge condensation has been reported to improve the hole mobility of the SiGe-on-insulator (SGOI). Our previous studies have shown that the higher Ge fraction of Si1-xGex nano-wire exhibits higher sensitivity. In this work, we investigated the effect of different oxidation recipe to provide information on the sensitivity of SiGe nano-wire. The 3-amino-propyltrime-thoxy-silane (APTMS) is used to modify the nano-wire's surface potential. Induced sensitivity characteristics of the samples were preformed to estimate the improvement effect. The mixed N-2/O-2 oxidation process with optimization ratio can be an effective technology to improve the sensitivity of SGOI nano-wires.
OXIDATION STUDY OF GE CONDENSATION ON SGOI NANOWIRE BIOSENSOR FABRICATION
(2013-01-01)
Chang, Kow-Ming
;
Chen, Chu-Feng
;
Lai, Chiung-Hui
;
Wu, Chin-Ning
;
Hsieh, Cheng-Ting
The Ge condensation method is effective in increasing the Ge fraction of Ge in SGOI. Previous studies by the authors confirmed a correlation between the Ge fraction and the sensitivity of the SiGe nano-wire sensor. To understand how Ge condensation on an SGOI nano-wire sensor helps to optimize oxidation conditions and sensitivity, the effect of oxidizing gas and the SiGe/alpha-Si stacked structure on the movement of Ge is investigated. The analytical results reveal that the sensitivity of SiGe nano-wires can be optimized by stacking an Si1-xGex layer that contains 14% Ge on a 200 angstrom-thick alpha-Si layer and treating the stack with O-2 gas diluted by 13% N-2 for 3 min.
Sensitivity enhancement in SiGe-on-insulator nanowire biosensor fabricated by top surface passivation
(2012-08-01)
Lai, Chiung-Hui
;
Chang, Kow-Ming
;
Chen, Chu-Feng
;
Hsieh, Cheng-Ting
;
Wu, Chin-Ning
The oxidation caused by Ge condensation increases the Ge fraction in a SiGe-on-insulator (SGOI) and significantly increases the hole mobility. This effect can be exploited to improve the sensitivity of SGOI nanowires. However, previous studies have found that the sensitivity of SGOI nanowires degrades when the Ge fraction exceeds 20%, because a high Ge fraction destabilises the surface state of SiGe. In this work, a top surface passivation plasma-enhanced chemical vapour deposition SiO2 layer deposited on a Si0.8Ge0.2 nanowire improved its sensitivity by similar to 1.3 times that of the nanowire sample without a top passivation layer.
SURFACE PASSIVATION EFFECT IN SGOI NANOWIRE BIOSENSOR WITH HIGH GE FRACTION
(2012-01-01)
Chang, Kow-Ming
;
Chen, Chu-Feng
;
Lai, Chiung-Hui
;
Hsieh, Cheng-Ting
;
Wu, Chin-Ning
The increase of surface to volume ratio results in the enhancement of the sensitivity of the nanowires. Our previous studies have shown that the higher Ge fraction of Si1-xGex nano-wire improves the sensitivity of the nanowire biosensor as a result of carrier mobility enhancement in strain-Si. Increasing the fraction of Ge in SiGe-on-Insulator (SGOI) using Ge condensation by oxidation has obtained a significant enhancement in hole mobility, further improving the sensitivity of SGOI nanowire. However, the sensitivity of SGOI nanowire was degraded for exceeding a Ge fraction of 20% (i.e., high Ge fraction), resulting from the unstable surface state. In this work, a top surface passivation SiO2 layer was deposited on Si0.8Ge0.2 nanowire and the sensitivity was about 1.3 times greater than nanowire sample without the top passivation layer.
The alpha-Si/SiGe core/shell nano-wire as highly sensitive bio-sensor
(2011-01-01)
Chang, Kow-Ming
;
Chen, Chu-Feng
;
Lai, Chiung-Hui
;
Liu, Chung-Hsien
;
Wang, Yu-Bin
Reducing the width of a nano-wire increases its surface to volume ratio, increasing the sensitivity of its conductivity to charges on its surface. Our previous studies have shown that increasing the Ge fraction in Si1-xGex nano-wires improves their sensitivity as bio-sensing. In this work, an alpha-Si/SiGe core/shell nano-wire is successfully fabricated using side-wall spacer method. The maximum sensitivity of a nano-wire bio-sensor with an optimized alpha-Si/SiGe thickness ratio is investigated.