Gate-to-source voltage response in high-sensitivity amorphous InGaZnO4 thin-film transistor pH sensors

In this paper, we discuss our top-gate-effect-based high-sensitivity amorphous InGaZnO4 thin-film transistor (a-InGaZnO TFT) pH sensor from the viewpoint of gate-to-source voltage (Vgs) response to small pH step variations. The a-InGaZnO TFT pH sensor, whose sensitivity is as high as 450 mV/pH, shows Vgs response to a pH step change of 0.1 with negligible hysteresis and good linearity. Because the high sensitivity is based on the enhancement of parallel shift in the transfer characteristics through the top-gate effect, the Vgs range for detecting is randomly selected.

[1]  Seiya Kobayashi,et al.  Bottom-gate amorphous InGaZnO4 thin-film transistor pH sensors utilizing top-gate effects , 2014 .

[2]  W. Cho,et al.  Sensitivity enhancement of amorphous InGaZnO thin film transistor based extended gate field-effect transistors with dual-gate operation , 2013 .

[3]  Seiya Kobayashi,et al.  Characterization of Top-Gate Effects in Amorphous InGaZnO4 Thin-Film Transistors Using a Dual-Gate Structure , 2012 .

[4]  K. Takahashi,et al.  Amorphous In–Ga–Zn–O Dual-Gate TFTs: Current–Voltage Characteristics and Electrical Stress Instabilities , 2012, IEEE Transactions on Electron Devices.

[5]  D. M. Leeuw,et al.  Beyond the Nernst-limit with dual-gate ZnO ion-sensitive field-effect transistors , 2011 .

[6]  C. Schönenberger,et al.  Nernst limit in dual-gated Si-nanowire FET sensors. , 2010, Nano letters.

[7]  M. Nakata,et al.  Application of Exponential Tail-State Distribution Model to the Above-Threshold Characteristics of Zn-Based Oxide Thin-Film Transistors , 2009, IEEE Transactions on Electron Devices.

[8]  M. Nakata,et al.  Dual-Gate Characteristics of Amorphous $ \hbox{InGaZnO}_{4}$ Thin-Film Transistors as Compared to Those of Hydrogenated Amorphous Silicon Thin-Film Transistors , 2009, IEEE Transactions on Electron Devices.

[9]  G. Shalev,et al.  Gain optimization in ion sensitive field-effect transistor based sensor with fully depleted silicon on insulator , 2008 .

[10]  Michael J. Schöning,et al.  An ISFET-based penicillin sensor with high sensitivity, low detection limit and long lifetime , 2001 .

[11]  S. D. Collins,et al.  A physical model for drift in pH ISFETs , 1998 .

[12]  Michael S. Shur,et al.  Physics of amorphous silicon based alloy field‐effect transistors , 1984 .

[13]  Seiya Kobayashi,et al.  High Sensitivity pH Sensors based on Amorphous Indium-gallium-zinc Oxide Thin-film Transistors , 2015 .

[14]  Seiya Kobayashi,et al.  Sensitivity Evaluation on Amorphous InGaZnO4 Thin-Film Transistor pH Sensors Having Various Capacitances of Ion-Sensitive and Bottom-Gate Insulators , 2014 .

[15]  M. Esashi,et al.  Methods of isfet fabrication , 1981 .