Simulation and Performance Evaluation of Charge Plasma Based Dual Pocket Biosensor using SiGe-Heterojunction TFET Design

Conventional biosensor designs are often vulnerable to issues like random dopant fluctuations (RDFs) and high thermal budgets due to their design and the device they are based on. The main reason behind such issues is the complexity of maintaining uniform doping levels throughout the device structure. This manuscript investigates a biosensor structure utilizing a dual pocket junctionless SiGe-Heterostructured TFET design to overcome such shortcomings. The implementation of the doping charge plasma technique with the uniform doping of 1×1015cm-3\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathrm {1}\times \mathrm {10}^{\mathrm {15}} {cm}^{\mathrm {-3}}$$\end{document} along an integrated SiGe-Heterostructure layer has improved the tunneling process while also effectively eliminating issues like random dopant fluctuations (RDF). Again the overall performance also depends on the sensitivity of the sensor design. Increasing the trapping area for biomolecules at the same technological node by increasing the pocket length or by adding a pocket region leads to rapid changes in the sensor’s electric properties owing to shifting dielectric constants (k) and charge densities (in both positive and negative situations), improving in the overall detection process. The influence of these parameters on the device’s Drain current, Surface Potential, Electron Tunneling Rate (ETR), Subthreshold Swing (SS), and Ion/Ioff ratio is also explored. The introduction of the added pocket region gives us scalability while also showing a higher sensitivity of 5.38×109\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathrm {5.38} \times \mathrm {10}^{\mathrm {9}}$$\end{document} for a dielectric constant being 12 and neutrally charged while rising to nearly 1.43×1010\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathrm {1.43} \times \mathrm {10}^{\mathrm {10}}$$\end{document} if the molecules are positively charged. With the improvement in drain current sensitivity due to the additional pocket and junctionless design, this work will undoubtedly give researchers a roadmap for the future generation of highly sensitive biosensor alternatives.