CS-FET Gas Sensor Array for Multi-Gas Food Spoilage Detection

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Solution Overview

Problem

Existing gas detection technologies for food quality monitoring are not cost-effective, power-efficient, and size-efficient, and lack the ability to simultaneously and accurately detect multiple gases associated with food spoilage, leading to limited sensitivity and reproducibility in mass production.

Innovation Solution

A multi-gas sensor array comprising silicon-based chemical-sensitive field effect transistors (CSFETs) decorated with different materials to detect specific gases, such as Ru for ammonia, Ag for hydrogen sulfide, and SiOx for humidity, which are fabricated using silicon complementary metal oxide semiconductor (CMOS) processing, enabling simultaneous and sensitive detection at room temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional gas detection sensors are used for food quality monitoring, then gas detection capability is provided, but cost-effectiveness, power efficiency, and size efficiency are poor

Engineering Contradiction:

Improvefood quality monitoring capabilityVSAvoidsensor size and power consumption

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The sensor system is segmented into multiple CSFET devices, each decorated with different materials to detect specific gases (ammonia, hydrogen sulfide, carbon dioxide). This segmentation allows parallel detection of multiple spoilage indicators simultaneously, improving monitoring capability while keeping each individual sensor compact and low-power

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The CSFET platform provides multi-functionality by detecting multiple gas types through material decoration. A single CSFET device can be configured to detect different gases by applying appropriate sensing materials, making the system universally applicable for comprehensive food spoilage monitoring without requiring multiple specialized sensors

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If single-gas detection sensors are used, then specific gas detection is achieved, but the ability to simultaneously detect multiple gases is limited

Engineering Contradiction:

Improvegas detection sensitivityVSAvoidmulti-gas detection capability

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The detection system is divided into multiple CSFET sensors, each optimized for detecting a specific gas through material decoration. This segmentation maintains high measurement precision for each target gas while enabling simultaneous multi-gas detection through the array configuration

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different sensing materials are applied to decorate the CSFET devices to create composite sensing structures. Each material-composite is specifically designed to interact with target gases (ammonia, hydrogen sulfide, carbon dioxide), providing both high sensitivity for specific detection and versatility for multi-gas monitoring

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If conventional sensor materials are used, then manufacturing is straightforward, but sensitivity and reproducibility in mass production are limited

Engineering Contradiction:

Improvesensor fabricationVSAvoiddetection sensitivity and reproducibility

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The sensing performance is optimized by changing material parameters through decoration techniques. By controlling the deposition parameters (thickness, composition, structure) of the sensing materials on CSFET gates, high detection sensitivity and reproducibility are achieved while maintaining compatibility with standard semiconductor manufacturing processes

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Traditional mechanical or chemical sensing methods are replaced with field-effect transistor-based detection. The CSFET platform uses electrical field effects to detect gas interactions, substituting mechanical/chemical measurement systems with electronic detection that offers higher precision, better reproducibility, and easier integration with modern manufacturing

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 multi-gas sensor array achieves high sensitivity, low power consumption, minimal hysteresis, and excellent selectivity, allowing for trace-level gas detection and real-time monitoring of food spoilage, reducing food waste and ensuring food safety.

Implementation Method 1

chemical sensitive field effect transistor (CSFET) sensors formed on a surface of the silicon substrate

Methodology Applied

Scientific EffectField effect transistor sensing: Electric Field

Implementation Method 2

each one of the plurality of CSFET sensors are decorated with a different material to detect a different gas

Methodology Applied

Scientific EffectAdsorption: Adsorption

Data Source

PatentUS12480910B2Multi-gas detection with CS-FET arrays for food quality assessment

Publication Date: 2025.11.25 RGT UNIV OF CALIFORNIA

AI summary

A multi-gas sensor to detect food spoilage and a method of forming the same are disclosed. The multi-gas sensor includes a silicon substrate and a plurality of chemical sensitive field effect transistor (CSFET) sensors formed on a surface of the silicon substrate, wherein each one of the plurality of CSFET sensors are decorated with a different material to detect a different gas associated with food spoilage.