Silicon MEMS resonator and method for realizing frequency drift self-compensation by piezoresistive heat of silicon MEMS resonator body

Abstract

The invention discloses a silicon MEMS resonator and a body piezoresistive thermal frequency drift self-compensation method thereof, an MEMS oscillator excitation electrode gives an alternating current excitation signal to the resonator, the frequency is equal to the frequency of the resonator, so that the resonator oscillates, a detection electrode divides a collected resonator oscillation signal into two paths, and the two paths are connected with the detection electrode. One path passes through a closed-loop oscillation system to realize closed-loop oscillation, the other path is transmitted to a frequency reading device, the frequency reading device acquires signal frequency and transmits frequency data to a frequency-voltage processing module in real time, the frequency-voltage processing module processes the signal frequency, and the frequency-voltage processing module outputs the processed signal data to a power supply. An error between an actual frequency and a set frequency is converted into a voltage signal, digital-to-analog conversion of the voltage signal is realized through a digital / analog voltage conversion module, a piezoelectric signal is input into electrodes at two ends of an MEMS resonant structure, a bias voltage is changed, so that piezoresistive heat generated by the MEMS resonator is changed, and the oscillation frequency is always stabilized near the set frequency; and frequency drift compensation is realized.

Description

technical field [0001] The invention belongs to the technical field of micro-electromechanical systems, and in particular relates to a silicon MEMS resonator and a method and system for self-compensating frequency drift through piezoresistive thermal realization of its body. Background technique [0002] In recent years, MEMS resonators have the ability to replace traditional quartz crystal oscillators due to their miniaturization, high integration with CMOS electronics, small frequency drift due to inertial acceleration, low impurity packaging, and strong shock resistance. Get a wide range of applications. How to improve the frequency stability of MEMS resonators and reduce phase noise has attracted the attention of scholars. [0003] The frequency offset factors of the resonator include changes in ambient temperature, vibration, changes in inertial force, aging, etc. The combination of these factors makes the stability of the resonator decrease with the increase of oscill...

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Problems solved by technology

It has a great influence on the stability of the output frequency of the resonator. In addition, the frequency of the resonator will change with the aging of the material as the service time increases. Therefore, passive and active compensation methods usually reduce temperature sensitivity and aging rate.

[0004] For the temperature compensation method used in the past active compensation method, the equipment is complicated, not only the temperature sensor needs to be installed, but also the environmental heat source needs to be designed. Since the MEMS resonator is at a micro scale, the layout of the heat source and temperature sensor and the spatial distance from the MEMS resonator will be affected. Affects temperature control accuracy. This method has problems such as uncertain temperature field distribution and heat conduction delay. In addition, this compensation method consumes a lot of power

[0005] For the voltage-controlled compensation method used in the past active compensation method, it is the compensation generated by adjusting the frequency of the resonator itself through the bias voltage, and the actual temperature of the oscillator is the same as the ambient temperature, so it cannot maintain the working environment temperature of the resonator. Stablize

It cannot make up for the influence that the residual stress generated due to technological reasons will affect the working state of the sensor as the temperature changes during the processing process.

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