Poly-Crystalline Silicon Nanowire Field Effect Transistor for

• Main Authors: Hsiao, Cheng-Yun, 蕭程允
• Other Authors: Yang, Yuh-Shyong
• Format: Others
• Language: en_US
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/22354556467215645059

博士 === 國立交通大學 === 生物科技學系 === 98 === A simple and low-cost method to fabricate poly-silicon nanowire field effect transistor (poly-Si NW FET) for biosensing application was demonstrated. The poly-silicon nanowire (ploy-Si NW) channel was fabricated by employing the poly-silicon (poly-Si) sidewall spacer technique, which approach was comparable with current commercial semiconductor process and forsaken expensive E-beam lithography tools. The electronic properties of the poly-Si NW FET in aqueous solution were found to be similar to those of single crystal silicon nanowire field effect transistors. Passivation of defects in the poly-SiNW by H+ or OH- contained in the aqueous solution is proposed to explain the phenomenon. First, two experiments of biotin-avidin/streptavidin and boronic acid-dopamine sensing with ID-VG measurement were used to demonstrate the biological and chemical species sensing capacity of poly-Si NW FET. Specific changes were observed for electric measurements made with nanowire surface modified with biotin or boronic acid for avidin/streptavidin and dopamine sensing. The changes of ID-VG curves were consistent with an n-type FET affected by a nearby negatively and positively charged molecules, respectively, and demonstrated sensitive and label-free senisng capacity. Then, we have demonstrated that the sensitivity of an NW biosensor can be electrically modulated through liquid gating. Our findings open a window toward understanding how liquid gating can be used to electrically modulate the sensitivities of biosensors to their limits. Final, we test the device with conductance-time detection of EV71 DNA oligonucleotides. The results indicate that less as 1fM EV71 DNA target to the EV71 DNA probe modified poly-Si NW FET may induce the observed conductance-time curve changes. This unique electronic property together with its high sensitivity, simplicity, low-cost manufacturing and potential for mass commercial production makes the poly-Si NW FET very attractive for applications as transducer of biosensing device.