Dual-Gate Vertical Biosensor Layout for Differential Analyte Sensing
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Solution Overview
Problem
Existing biosensors face challenges in achieving high sensitivity and signal-to-noise ratio due to their miniaturized form-factor and integration with CMOS technology, limiting their ability to detect and characterize target analytes effectively.
Innovation Solution
A dual-gate vertical field-effect transistor (VFET) biosensor is developed, where a shared trench between n-type and p-type VFETs allows simultaneous measurement of electrical responses to determine the presence and concentration of an analyte, leveraging scaled VFET technologies for a small footprint and dense integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single VFET is used for biosensing, then the device structure is simple, but the sensitivity and signal-to-noise ratio are limited
Solution Approach 1:
The biosensor is segmented into two complementary VFETs (n-type and p-type) with identical geometries but opposite polarity channels. Each VFET functions as an independent sensing element, allowing differential measurement that enhances sensitivity and signal-to-noise ratio while maintaining compact integration
Solution Approach 2:
Two complementary VFETs are merged into a single integrated biosensor structure sharing common substrate and fabrication processes. The complementary pairing enables differential sensing that amplifies the measurement signal while rejecting common-mode noise, resolving the contradiction between enhanced measurement precision and device complexity
2Productivity
If miniaturized form-factor is achieved for CMOS integration, then device density increases, but detection capability of target analytes deteriorates
Solution Approach 1:
The VFETs are configured with vertical channel orientation perpendicular to the substrate surface, utilizing the vertical dimension for current flow while maintaining a compact lateral footprint. This dimensional transition enables high device density for CMOS integration while preserving sufficient channel volume for effective analyte detection
Solution Approach 2:
The complementary VFET pair is designed with identical miniaturized geometries optimized for CMOS compatibility. By segmenting the sensing function into two closely-integrated devices with complementary characteristics, the design achieves high device density while the differential measurement approach maintains detection capability despite reduced individual device dimensions
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 dual-gate biosensor achieves higher sensitivity and signal-to-noise ratio compared to single VFETs, enabling detection of target analytes with improved accuracy and integration with other chip components.
Implementation Method 1
simultaneously measuring a first electrical response of the n-type VFET and a second electrical response of the p-type VFET
Data Source
AI summary
Embodiments relate to a vertical transistor dual gate biosensor. A technique includes forming a first vertical field-effect transistor (VFET) having a first gate and forming a second VFET having a second gate. The first and second gates include a shared trench formed in between the first VFET and the second VFET, where the first gate includes a first sidewall of the shared trench, and where the second gate includes a second sidewall of the shared trench. The first sidewall is opposite the second sidewall in the shared trench.