Dual Surface Charge Biosensor BJT Architecture
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional biosensors face limitations in detecting high radiation rates and energy of incident radiation, and they require time for readout, which restricts their portability and real-time monitoring capabilities, especially in measuring trace amounts of substances.
Innovation Solution
A monolithic biosensor with embedded fluid channels and a vertically oriented lateral bipolar junction transistor (BJT) device is developed, capable of sensing both positive and negative surface charges using NPN and PNP BJTs, with a dielectric layer to reduce ion drift effects and enhance sensitivity through a 60 mV/decade slope detection mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional biosensors are used to detect biological materials, then detection capability is provided, but real-time monitoring and portability are limited due to processing time requirements
Solution Approach 1:
The patent replaces conventional biosensor detection mechanisms with a BJT-based electrical detection system. The BJT device directly converts biological material presence into electrical signals through charge-induced base current modulation, eliminating the need for time-consuming chemical reactions or optical processing. This substitution enables real-time detection while maintaining high sensitivity.
Solution Approach 2:
The patent utilizes the BJT's base current parameter as the detection output, which changes in response to surface charges from biological materials. By monitoring the base current rather than relying on reaction-based signals, the system achieves rapid real-time detection without sacrificing measurement precision.
2Measurement precision
If conventional biosensors are used to detect trace amounts of substances, then detection is possible, but portability is restricted due to requirement for special laboratory instruments
Solution Approach 1:
The patent replaces complex laboratory instrumentation with a compact BJT-based detection system integrated on a semiconductor substrate. The BJT's inherent signal amplification capability through current gain (β) enables trace amount detection without requiring bulky external equipment, thus achieving both high precision and portability.
Solution Approach 2:
The patent integrates the BJT device, sensing structure, and control circuitry into a single monolithic semiconductor device. This integration combines detection, signal processing, and control functions into one portable unit, eliminating the need for separate laboratory instruments while maintaining trace amount detection capability.
3Adaptability or versatility
If NPN and PNP BJTs are used for sensing positive and negative charges, then dual charge detection capability is achieved, but device complexity increases
Solution Approach 1:
The patent integrates both NPN and PNP BJT devices on a single semiconductor substrate with shared structural elements. The common base region and integrated sensing structure reduce the overall device complexity compared to separate detection systems, while maintaining the versatility to detect both positive and negative charges simultaneously.
Solution Approach 2:
The patent designs the BJT-based sensing structure to universally detect both polarities of surface charges through the same fundamental mechanism. The NPN and PNP devices use identical sensing principles but respond to opposite charge signs, providing dual detection capability without requiring fundamentally different detection systems.
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 biosensor enables simultaneous detection of both positive and negative charges with improved sensitivity and signal amplification, allowing for real-time monitoring of trace amounts of substances and enhanced portability by integrating with standard CMOS control and processing circuitry.
Implementation Method 1
The dielectric layer is configured to respond to charges in biological molecules, the charges being converted to a sensing signal by the BJT
Implementation Method 2
The barrier layer is configured to reduce a drift effect caused by ions from a biological molecule being tested from penetrating into the dielectric layer of the sensing structure
Data Source
AI summary
A biosensor includes a bulk silicon substrate and a vertical bipolar junction transistor (BJT) formed on at least a portion of the substrate. The BJT includes an emitter region, a collector region and an epitaxially grown intrinsic base region between the emitter and collector regions. The biosensor further includes a sensing structure formed on at least a portion of two vertical surfaces of the intrinsic base region of the BJT. The sensing structure includes a channel/trench opening, exposing the intrinsic base region on at least first and second opposing sides thereof, and at least one dielectric layer formed in the channel/trench opening and contacting at least a portion of the intrinsic base region, the dielectric layer being configured to respond to charges in biological molecules.