Vertically Stacked Cascode BJT Sensor for In-Situ Low-Noise Amplification
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Solution Overview
Problem
Existing biosensors face challenges in efficiently amplifying weak biological signals while maintaining energy efficiency and integrating with readout/control circuitry, leading to noise buildup over long distances.
Innovation Solution
A vertically stacked cascode bipolar junction transistor pair is integrated with a sensing trench for in-situ amplification, featuring a dual-base configuration that enhances output resistance and voltage gain without increasing device footprint, utilizing III-V or group IV materials for low noise and enabling gravity-induced sample flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If biosensors are integrated with readout/control circuitry over long distances, then monolithic integration is achieved, but noise builds up during signal transmission
Solution Approach 1:
The patent transitions from lateral/horizontal signal transmission to vertical signal transmission by stacking the dual-base bipolar junction transistor sensor and amplifier circuit vertically. This dimensional change allows the sensing element and amplification circuit to be positioned in close vertical proximity, eliminating long-distance lateral connections that cause noise buildup while maintaining monolithic integration.
Solution Approach 2:
The patent implements nested structures where the dual-base bipolar junction transistor is integrated within the amplifier circuit structure. The sensing element is embedded in the amplifier circuit, allowing the signal to be amplified in-situ at the sensing location, thus eliminating the need for long-distance signal transmission and reducing noise accumulation.
2Object-affected harmful factors
If amplifier circuit is placed close to biosensor, then noise buildup is eliminated, but device footprint increases
Solution Approach 1:
The patent resolves the footprint issue by moving from a planar layout to a vertical stacked architecture. The dual-base bipolar junction transistor sensor and amplifier circuit are stacked vertically along the same footprint area, enabling close proximity placement without increasing the lateral device footprint. This vertical integration allows in-situ amplification while maintaining compact form factor.
Solution Approach 2:
The patent merges the sensing function and amplification function into a single integrated vertical structure. The dual-base bipolar junction transistor serves both as the sensing element and is directly coupled to the amplifier circuit, combining multiple functions into one compact unit that eliminates the need for separate sensing and amplification areas.
3Productivity
If vertically stacked cascode bipolar junction transistor pair is used, then signal amplification efficiency is improved, but device complexity increases
Solution Approach 1:
The dual-base bipolar junction transistor provides multi-functionality by serving as both the sensing element and being directly integrated with the amplifier circuit. This universal component performs multiple functions (sensing and signal amplification) in a single device, reducing the need for separate components and simplifying the overall system architecture despite the advanced transistor configuration.
Solution Approach 2:
The patent utilizes parameter changes in the bipolar junction transistor configuration, specifically employing the dual-base structure with modified electrical parameters to achieve high-gain amplification. By changing the transistor configuration parameters and operating conditions, the device achieves efficient signal amplification while managing the complexity through optimized electrical characteristics.
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 solution provides efficient signal amplification with reduced noise, enabling dense and area-efficient biosensing systems that eliminate the need for pumps, while maintaining high performance and low power consumption.
Implementation Method 1
A vertically stacked cascode bipolar junction transistor pair is integrated with a sensing trench for in-situ amplification, featuring a dual-base configuration that enhances output resistance and voltage gain
Implementation Method 2
replacing the lower vertical spacer with a metal sensing surface, wherein a portion of a sidewall of the first sample trench is provided by the metal sensing surface
Implementation Method 3
utilizing III-V or group IV materials for low noise and enabling gravity-induced sample flow
Implementation Method 4
utilizing III-V or group IV materials for low noise and enabling gravity-induced sample flow
Data Source
AI summary
A sensor device includes a vertically stacked cascode bipolar junction transistor pair, and a first trench having a first sidewall, wherein a portion of the first sidewall is provided by the first sensing surface, wherein a bipolar junction transistor and a dual-base bipolar junction transistor of the cascode bipolar junction transistor pair are stacked vertically along the first trench.