Piezoresistive pressure sensor design method considering temperature influence

Abstract

The invention provides a piezoresistive pressure sensor design method considering temperature influence, the thermal zero drift and the thermal sensitivity drift of a piezoresistor are introduced to carry out full-temperature-zone performance analysis, and subsequent effective temperature compensation is facilitated; the method for obtaining the thermal zero drift and the thermal sensitivity drift comprises the following steps of: inputting the variation relationship between the resistivity and the temperature under different doping concentrations and the variation relationship between the piezoresistive coefficient and the temperature under different doping concentrations into a piezoresistive pressure sensor structure model constructed in finite element software COMSOL, and calculating to obtain a static output characteristic curve and a temperature drift characteristic curve, and finally obtaining thermal zero drift and thermal sensitivity drift. In order to overcome the defects of the design method of the piezoresistive pressure sensor, the temperature characteristic of the silicon piezoresistive material is combined with finite element simulation software COMSOL, the design of the piezoresistive pressure sensor considering the temperature influence is realized, the design method of the piezoresistive pressure sensor in the full temperature zone is provided, and an important theoretical support is provided for subsequent effective temperature compensation.

Description

technical field [0001] The invention relates to the technical field of measurement and testing, in particular to a piezoresistive pressure sensor design method considering the influence of temperature. Background technique [0002] Due to its good stability, high sensitivity, wide frequency response range, small size, and easy integration, piezoresistive pressure sensors have become fast-growing and widely used pressure sensors, and have been successfully used in aerospace, marine meteorology, etc. , process industry, biomedicine and other fields. However, the piezoresistive pressure sensor prepared based on diffused silicon process technology is easily affected by temperature because of the characteristic parameters of the silicon semiconductor material, and the minority carrier migration inside the piezoresistor strip causes the output of the sensor to be affected by temperature. Larger thermal zero point drift and thermal sensitivity drift are generated, so that under th...

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Problems solved by technology

Due to the limitation of the current manufacturing process level, it is impossible to ensure that the doping concentration on the surface of the varistor is completely consistent during ion implantation, resulting in inconsistent initial resistance values ​​of the four varistors.

(2) When the sensor heats up or the external temperature changes, different doping concentrations are subject to different thermal stresses, so the resistance of each piezoresistor changes differently under the same temperature condition, which is another reason for the zero temperature drift a reason

(2) The thermal expansion coefficient of the silicon material used to make the varistor is different from that of the insulating material to which it is attached. Additional thermal stress will be generated under the same temperature environment, which will cause the sensitivity to change.

(3) Sensitivity changes caused by uneven doping of piezoresistors

[0005] However, the existing piezoresistive pressure sensor design methods often only focus on the static output characteristics at room temperature, and rarely consider the design of its temperature influence, which brings difficulties to the overall performance evaluation of the sensor. It is urgent to find a universal, accurate sensor design method

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