Macro modeling of ion sensitive field effect transistor with current drift

作者：Kwon Dae Woong; Kim Sihyun; Lee Ryoongbin; Mo Hyun Sun; Kim Dae Hwan; Park Byung Gook^*

来源：Sensors and Actuators B: Chemical , 2017, 249: 564-570.

DOI：10.1016/j.snb.2017.03.110

• ISFET with CMOS circuit
• Drift effect mechanism
• Drift effect modeling
• Macro model of ISFET
• Circuit model of ISFET

In terms of the application of the ion sensitive field effect transistor (ISFET) fabricated with top-down approached and CMOS-compatible back-end process to integrated circuits, the macro model of the ISFET is required. Although several models have been reported, there is no electrical model that reflects the time-dependent drain current (I-D) change (drift effect). We propose the electrical model which can reflect the drift effect and can be expressed by the combination of electrical circuit components. In the proposed model, R-1 represents the resistance of the electrolyte and the FET can be approximated by the capacitances C-1 (capacitance of pure gate oxide in which hydrogen ions move very slowly) and C-2 (capacitance by gate oxide with defects in which hydrogen ions move relatively faster). Furthermore, the movement of hydrogen ions in the defective oxide is represented by R-2 and the current drift is modeled as the parallel combination of the C-2 and the R-2 because the drift effect is strongly related to hydrogen ion movement through defective gate oxide or Helmholtz layer. Consequently, the ISFET with the I-D drift can be modeled by the series connection of the RI, the parallel combination of the C-2 and the R-2, and the C-1. Also, The ID calculated by the proposed model is successfully fitted to the measured time-dependent ID of the ISFET.

• 出版日期2017-10