Hydrogen-ion Sensing Characteristics of Cavity Based Triple-Gate Junctionless Biofet for Enhanced Sensitivity


In this paper, a triple gate (TG) cavity based, polysilicon junctionless (JL) ion-sensitive field-effect transistor (ISFET) architecture has been proposed for the first time. The performance of the proposed device has been compared with conventionally doped ISFET. The effect of pH is investigated for different adhesion layers, device layer thickness (tsi), electrolyte thickness (te) and, channel lengths (L). Threshold voltage(\(\frac {\triangle {V_{th}}}{\triangle {pH}}\)) has been used as sensing metric for analysis and comparison. Besides, ION/IOFF ratio has also been measured for different pH. The average maximum threshold voltage sensitivity of the proposed device has been measured and found to be 72.5%, 49.5%, and 53.7% better than TG-conventional ISFET for different adhesion layers, device layer thickness, and channel lengths respectively. Furthermore, the effect of channel lenghth on threshold voltage sensitivity has also been studied. It is observed that the sensitivity increases with increase in channel length. The implementation and all the simulations have been performed by using the ATLAS device simulator.

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The authors acknowledge the Department of Science and Technology (DST) and science and engineering research board (SERB), Government of India for financial support under project no. ECR/2017/000216. The authors would also like to acknowledge the assistance from VLSI LAB under special man power development programme (SMDP) MNIT Jaipur.

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Correspondence to Jaydeep Singh Parmar.

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Parmar, J.S., Shafi, N. & Sahu, C. Hydrogen-ion Sensing Characteristics of Cavity Based Triple-Gate Junctionless Biofet for Enhanced Sensitivity. Silicon (2020). https://doi.org/10.1007/s12633-020-00526-x

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  • Biosensor
  • Junctionless (JL)
  • pH-sensor
  • Triple gate