Study of Junctionless GAA nanowire FETs with extended gate as Biosensors

• Main Authors: Chiang, Li-Chuan, 江莉娟
• Other Authors: Sheu, Jeng-Tzong
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/s5pcep

碩士 === 國立交通大學 === 材料科學與工程學系奈米科技碩博士班 === 104 === Integration of gate-all-around (GAA) silicon nanowire (NW) field-effect-transistor (FET) and extended gate as sensor for real-time detection of biomolecules in microfluidic system is the focus of this thesis. Both junctionless (JL) and inversion mode (IM) GAA nanowire FETs with 7-nm thick and 80-nm wide channel were prepared on the same chip for comparison. Both GAA NW devices exhibit outstanding electric properties such as a very steep subthreshold slope (SS; 63~71 mV/decade), a virtual absence of drain-induced barrier lowering (DIBL; 0 mV/V) and a high ON/OFF current ratio (~5×106, VD= 0.1 V). Then, capacitive extended gates were connected to JL and IM GAA nanowire FETs for both pH and biosensing in microfluidic system. For sensitivity of pH sensing, both the surface dielectric materials of extended gate and working regions of SiNW FETs under different gate voltages were investigated. By modification of APTES and NHS-biotin on the surface of extended gate, real-time streptavidin detections were evaluated. The reliability of modifications was justified by using the fluorescence technique and electrochemical impedance spectroscopy. Based on the experimental results, JL and IM GAA nanowire FETs are both applicable as biomolecule sensing transducers. However, JL GAA NW FETs need simpler fabrication process and thus provides high yield when preparing the devices.