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Piezoresistive microelectromechanical sensors (MEMS) in silicon are excellently suited for the measurement of various physical quantities such as pressure, force, flow, acceleration as well as a multitude of other derived quantities. They are characterized, among other things, by a high sensitivity with a small component size, and thus a high signal-to-noise ratio, high electronic stability as well as a very linear characteristic curve. Due to these outstanding properties as well as the comparatively low cost of MEMS-based piezoresistive signal converters, an expansion of the application and use range of such sensors is desirable.
Especially piezoresistive pressure sensors are usually designed for operating temperatures up to about 130°C.
The raw signals of the sensor element are processed by means of an ASIC. The calibration data for the temperature compensation of the output signal are also stored here. At present, hardly any commercial ASICs are available for applications in the extended operating temperature range. Up to now, the ASIC has been spatially separated from the measuring location of the pressure sensor chip. This leads to a reduction in measurement accuracy, an increase in installation space and an increase in manufacturing costs.
To solve this problem, an analog temperature compensation integrated on the sensor chip was designed and implemented for operating temperatures up to about 300°C, which offers the following advantages:
• No high-temperature ASICs are required for temperature compensation.
• Systematic temperature errors are avoided, which arise because the (conventional) ASIC is spatially separated from the location of the sensor and thus both locations have different temperatures (location of pressure measurement and location of temperature measurement). At the same time, the dynamics of the system are improved during temperature changes.
• The required installation space of the measuring system as well as its manufacturing costs can be reduced.

By adapting chip design and semiconductor technology, piezoresistive pressure sensor chips in the extended operating temperature range of +40°C to +300°C were developed and manufactured.
The result can also be applied to classic piezoresistive Si pressure sensors in the temperature range up to 130°C as analog precompensation. The advantage here is that fewer temperature support points are required for the calibrations, or depending on the desired accuracy, calibration can even be omitted altogether.

The research and development work described was funded by the German Federal Ministry of Economic Affairs and Climate Action (BMWK) in the research project "Analog Integrated Temperature Compensation for High-Temperature Applications" (ANITHA).
Funding code: 49MF180042