Fabrication and Application of Double-Gate Poly-Si with Horn-Like Nanowire Sensors

• Main Authors: Cheng, Fang-Ching, 鄭方晴
• Other Authors: Chao, Tien-Sheng
• Format: Others
• Language: en_US
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/25408567729962954179

碩士 === 國立交通大學 === 電子物理系所 === 102 === Biosensors have gathered great importance in recent years with the rapid development of technology, thus we hope to bring more benefit for people to achieve an easily biomedical sensing environment. In order to obtain a better signal response, nanowire field effect transistors are emerging as powerful sensors for detecting chemical/biological species. We proposed the novel horn-like poly-Si nanowire biosensors by using spacer technology which is complementary metal-oxide- semiconductor (CMOS) compatible for pH and biomolecule detection with low cost and high sensitivity. The poly-Si nanowire is fabricated by using the trapezoidal-shape dummy gate structure with the spacer wire process to form the special shape of horn-like nanowire. The horn-like sharp inducing a strong electrical field which operates in the bottom-gate mode will limit the drain current with different liquid gate voltage. We use this phenomenon to find a largest difference of the drain current between liquid gate voltage at 2V and 3V as a best real time sensing condition. The horn-like nanowire sensors exhibited a higher sensitivity to 132.9mV/pH exceeding Nernst limit at bottom-gate mode operation amplified by capacitive coupling. However, the actual CMOS readout signal has not been effectively improved by this way. Moreover, a new method for detection of pH and biomolecule from current of horn-like nanowires structure is suggested. The significant change in the drain current with real-time measurement was shown when the specific binding occurred between antibody and antigen of ferritin. Hence, the horn-like nanowires show a promising potential for the development of biosensors.