Performance Assessment of a New Gaussian-doped Junctionless ISFET: A Numerical Study

Recently, a major research focus has been devoted to the development of ISFET sensors for future biomedical, environmental and food-processing sensing applications using special taste sensors based on Ion Sensitive Field-Effect Transistor (ISFET) technology. This has resulted in various sensor designs attracting increased interest by the research community as demonstrated by a number of proposed designs. In this work, we propose to relax the ISFET concept by dropping the junction of the ISFET design, hence proposing a new JL ISFET (junctionless ISFET) sensor structure based on a Gaussian doping (GD) profile strategy. The electrical parameters and performances of the proposed pH sensor are numerically analyzed, where the sensitivity properties are reported. In this context, we address the influence of a modified channel doping profile with a Gaussian shape on the variation of the sensor Figures of Merit (FoM) parameters, such as power consumption, thermal stability, leakage current and sensitivity. The proposed design also exhibits an enhanced threshold voltage shift with a varying pH of the solution resulting in improved electrical and sensitivity behavior characteristics. The results have demonstrated that the proposed design provides promising pathways for enhancing the ISFET performances as compared to the conventional FET-based sensor counterparts where the recorded sensitivity reaches 66.3 mV/pH. Furthermore, the results obtained clearly show the excellent pH modulation of the channel conductivity performance. Therefore, the proposed structure demonstrates the effectiveness of the adoption of a Gaussian-doped JL ISFET design as a potential candidate for high-performance and ultra-low power FET-based sensing applications as demonstrated from the proportional improvement in both the device electrical performance and the sensor sensitivity.