Simulation-based Study of Super-Nernstian pH Sensor Based on Doping-less Tunnel-field Effect Transistor

• Published in: SILICON 2023-07, Vol.15 (10), p.4285-4296
• Main Authors: Rasool, Zuber, Amin, S. Intekhab, Majeed, Lubna, Bashir, Ishrat, Seraj, Anjar, Anand, Sunny
• Format: Article
• Language: English
• Subjects: Aluminum oxide; Chemistry; Chemistry and Materials Science; Dielectrics; Doping; Energy bands; Environmental Chemistry; Field effect transistors; Germanium; Inorganic Chemistry; Lasers; Materials Science; Optical Devices; Optics; Original Paper; Photonics; Polymer Sciences; Production costs; Semiconductor devices; Sensitivity; Simulation; Transistors
• ISSN: 1876-990X; 1876-9918
• DOI: 10.1007/s12633-023-02329-2

In this work, we have simulated doping less tunneling field-effect transistor (DL-TFET) based pH sensor which can detect the pH variation in an aqueous (electrolyte) medium. The source-sided underlapped technique is employed to achieve better sensitivity. The simulated results were extracted with the help of the software package TCAD-Silvaco. In this work, we have compared the pH sensing capabilities of both conventionally doped TFET (C-TFET) and DL-TFET having the same configuration. Result suggests that the sensitivity of DL-TFET is equal to that of C-TFET. Since DL-TFET already exhibits superiority over C-TFET in terms of better immunity against random doping fluctuations (RDF), low fabrication cost and complexity, it can be used as a better alternative to C-TFET based ISFETs. Furthermore, in this work, we have discussed and demonstrated how the performance and sensitivity of the DL-TFET device can be further increased by the use of low energy band materials like germanium in the source region and high K dielectric materials like Al 2 O 3 as a sensitive oxide layer underneath the underlapped region. The voltage sensitivity achieved by DL-TFET in this work is 312 mV/pH which surpasses the Nernst limits by more than 5 times.