Effect of Sensing Film Thickness on Sensing Characteristics of Dual-Gate Poly-Si Ion-Sensitive Field-Effect-Transistors

Recent advances in ion‐sensitive field‐effect transistors for biosensing applications

“…Yen et al further studied the relations between pH sensitivity and the thickness of the sensitive layer in dual-gate ISFETs. [112] An increase in the thickness would reduce the capacitance of the sensing membrane, resulting in lower sensitivity according Review doi.org/10.1002/elsa.202100163 F I G U R E 4 Ion-sensitive field-effect transistors (ISFETs) with different gate structures. (a) Unmodified complementary metal-oxide-semiconductor (CMOS) gate.…”

“…further studied the relations between pH sensitivity and the thickness of the sensitive layer in dual‐gate ISFETs. [ 112 ] An increase in the thickness would reduce the capacitance of the sensing membrane, resulting in lower sensitivity according to the capacitive coupling. Besides, Zhou et al.…”

Polycrystalline-silicon-based double-gate ion-sensitive field-effect transistors using APTES/SiO2 stack-sensing membrane

“…2,6,7) Therefore, to break through the limit, a doublegate (DG) structure was recently proposed. 3,8,9) Compared to the conventional ISFETs, DG-ISFETs have an additional bottom gate. Furthermore, by the capacitive coupling effect between the top and bottom gates, the voltage shifts due to the surface reaction could be multiplied with an amplifying factor (AF), and the sensitivity could be significantly enhanced.…”

“…Silicon-on-insulator (SOI) or thin-film transistors (TFTs) were employed to fabricate DG-ISFETs. [8][9][10][11] However, the cost of the SOI substrate is very high, and the fabrication of the metal oxide-based TFT structure is unstable. The polycrystalline-silicon (poly-Si) TFT technique has been well established and is wildly used for displays and threedimensional integrated circuit (3D-IC) applications 12,13) owing to its advantage, such as high mobility, low leakage current, and the probability of system integrating on panels 14,15) or CMOS-ICs.…”

“…However, the properties of the sensing membrane were the main issue as a pH sensor. 8,9,11) To improve the properties of the sensing membrane, highk materials, Si 3 N 4 , Ta 2 O 5 , and Al 2 O 3 were often used. [16][17][18][19] Using the self-assembled monolayers is an alternative method to increase the reactive sites on the sensing membrane.…”