Numerical simulation of ISFET structures for biosensing devices with TCAD tools

Area of Science:

• Semiconductor Device Physics
• Biotechnology
• Computational Modeling

Background:

• Ion-Sensitive Field Effect Transistors (ISFETs) are foundational for biosensor fabrication.
• Optimizing biosensor design requires understanding the link between fabrication parameters and electrical response.
• Electrical device-level simulation offers a method to achieve this optimization.

Purpose of the Study:

• To present a numerical simulation approach for studying ISFET structures in biosensing devices (BioFETs).
• To utilize Synopsys Sentaurus Technology Computer-Aided Design (TCAD) tools for this simulation.
• To establish a framework for optimizing biosensor design and fabrication.

Main Methods:

• Simulated the electrostatic behavior (transfer characteristics) of a general BioFET structure.
• Modified custom material properties to replicate electrolyte behavior within the simulation.
• Set intrinsic semiconductor material parameters to model an electrolyte solution.

Main Results:

• Simulated BioFET response with increasing captured target numbers (1-10).
• Calculated drain current (ID) versus drain-source voltage (VDS) for various charged block positions and reference electrode values.
• Observed that target location, not just number, significantly influences current modulation.

Conclusions:

• A numerical simulation approach using Synopsys Sentaurus TCAD for ISFET-based biosensors was successfully developed.
• This framework aids in optimizing biosensor design, reducing development time and cost.
• Key finding: Target proximity to the source region yields greater current modulation efficiency compared to the drain region; random distribution is more effective than localized grouping.