CMOS Ion-Sensitive Field Effect Transistors for DNA Detection

• Main Authors: Chang, Chieh-Feng, 張界烽
• Other Authors: Lu, Shiang-Cheng
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/mzza2h

碩士 === 國立清華大學 === 電子工程研究所 === 107 === How to detect the disease of a patient is a very important issue in medical treatment. According to statistics, one third of people has been infected with hepatitis B virus, and the region of the highest hepatitis prevalence in the world occurs in Taiwan. If there is a rapid and simple method to detect a lower concentration of hepatitis B viral load in serum, it facilitates early diagnosis of hepatitis B virus infection and prevention of further transmission. Ion-sensitive field-effect transistors are presented in this case to get a real-time detection of a lower concentration DNA molecules (fM level). Ion-sensing field-effect transistors are fabricated using TSMC 0.35μm CMOS process. And then surface functionalization and DNA molecules are modified on the passivation of sensors by Self-assembled monolayers. In terms of circuit design, we design different sizes of ISFETs with interdigitated electrodes or planar electrodes to explore the characteristics of the sensors. The best sensitivity of the designs in this case is 32mV/pH. In the end, this scheme can be combined with the readout circuit for the measurement of several sensors and convert the ISFET current to a digital output signal. Due to DNA molecules have the negatively electrical property, the output frequency will be increased when target DNAs hybridize with probe DNAs.