Dual-Gate BioFET CMOS Fabrication Sensitivity
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Solution Overview
Problem
Existing BioFETs face challenges in fabrication and operation due to compatibility issues between semiconductor fabrication processes and biological applications, particularly in integrating electrical signals and achieving large-scale integration, which affects sensitivity and reliability.
Innovation Solution
A BioFET device is fabricated using complementary metal-oxide-semiconductor (CMOS) compatible processes, featuring a gate structure with a bio-compatible interface layer and receptor molecules for biomolecule detection, allowing for label-free operation and improved sensitivity through dual-gate configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional BioFET fabrication processes are used, then device structure is formed, but compatibility issues with biological applications and semiconductor fabrication processes arise
Solution Approach 1:
The device is segmented into two separate gates: a front gate for electrical control and a back gate for biological sensing. This segmentation allows each gate to be optimized for its specific function, with the front gate interface compatible with standard CMOS fabrication and the back gate interface optimized for biological molecule interaction, thereby resolving the compatibility conflict between semiconductor manufacturing and biological applications
Solution Approach 2:
An interface layer is introduced as an intermediary between the semiconductor substrate and the biological sensing layer. This interface layer acts as a mediator that is compatible with both semiconductor fabrication processes and biological applications, enabling reliable operation by bridging the gap between the two domains
2Measurement precision
If single-gate BioFET configuration is used, then device complexity is reduced, but detection sensitivity is insufficient
Solution Approach 1:
The single gate is segmented into two separate gates positioned on opposite sides of the semiconductor substrate. The front gate provides electrical control while the back gate enhances sensitivity to biological molecules. This segmentation doubles the sensing capability without requiring a completely new device architecture, achieving improved sensitivity with manageable complexity
Solution Approach 2:
The dual-gate structure provides multi-functionality: the front gate handles electrical control and signal amplification while the back gate is optimized for biological sensing. This universal design allows the same device structure to perform both electrical and biological functions efficiently, improving detection sensitivity without proportionally increasing device complexity
3Measurement precision
If dual-gate configuration is implemented, then detection sensitivity is improved, but parasitic capacitance and bulk substrate effects increase
Solution Approach 1:
The interface layer serves as an intermediary that electrically isolates the two gates while allowing mechanical and biological interaction. This intermediary reduces parasitic capacitance between the gates by providing electrical separation, thereby mitigating the harmful capacitive effects that would otherwise reduce detection sensitivity in a dual-gate configuration
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The CMOS-compatible BioFET device enhances detection sensitivity and reliability by reducing parasitic capacitance and bulk substrate effects, enabling efficient biomolecule detection with improved signal amplification and reduced operational complexity.
Implementation Method 1
The interface layer is operable to provide a binding interface for at least one of a biomolecule and a bio-entity
Implementation Method 2
a gate structure (202) formed on a substrate (214), a source region (204) and a drain region (206) formed in the substrate (214) adjacent the gate structure (202), and a channel region (208) interposing the source and drain regions and underlying the gate structure (202)
Data Source
AI summary
The present disclosure provides a bio-field effect transistor (BioFET) and a method of fabricating a BioFET device. The method includes forming a BioFET using one or more process steps compatible with or typical to a complementary metal-oxide-semiconductor (CMOS) process. The BioFET device may include a substrate; a gate structure disposed on a first surface of the substrate and an interface layer formed on the second surface of the substrate. The interface layer may allow for a receptor to be placed on the interface layer to detect the presence of a biomolecule or bio-entity. An amplification factor of the BioFET device may be provided by a difference in capacitances associated with the gate structure on the first surface and with the interface layer formed on the second surface.