Metal oxide gas sensors

SGX has a proprietary MOS technology utilizing state of the art MEMS technology, combining a specialized nano-particle sensing layer with a patented poly-silicon heater.

This unique design creates a highly sensitive and responsive semiconductor sensor, manufactured on an automotive production line for outstanding quality and

The basic principle behind metal oxide sensors is that the resistance of the detecting layer in sensor changes in the presence of the target gasses. For oxidizing gases such as ozone or nitrogen dioxide the resistance will increase; for reducing gases such as carbon monoxide or VOC’s the resistance will go down.

In very simple terms reducing gases remove some of the insulative oxygen species at the grain boundaries thus causing the overall resistance to go down. Alternatively oxidizing gases add to the insulative oxygen species causing the resistance to increase. These reactions occur at elevated temperatures and hence the sensing layer needs to be heated with the integrated heater.

It is one of the main advantages of the SGX sensor that the power required to heat and run the sensor are less than other types on the market.

The change in resistance with the change in gas concentration is not a linear response. The response can be measured and fitted to a polynominal relation. Because of this and other factors, the sensors are best employed where the end user is looking to detect instances or trends of gas presence rather than seeking to obtain high accuracy, such as that achieved by more sophisticated analytical type systems. For these event sensing applications the level of accuracy is required is not great and there are unlikely to be safety related issues.

Amphenol SGX Sensortech has a proprietary MOS technology utilizing state of the art MEMS technology, combining a specialized nano-particle sensing layer with a patented poly-silicon heater.

This unique design creates a highly sensitive and responsive semiconductor sensor, manufactured on an automotive production line for outstanding quality and performance.

These sensors are easily capable to detect and measure combustible and pollution gasses in parts per billion (PPB) and are suitable for many environmental, automotive and industrial applications worldwide.

Main features of the metal oxide gas sensors

• Low heater current
• Wide detection range
• High sensitivity
• Available in SMD packages
• High resistance to shocks and vibrations
• Miniature dimensions
• Long life expectancy
• Has the benefit of a patented low power heater design
• Very fast thermal response Electrostatic discharge protected
• Suitable for measurement or alarm warning applications.

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