The Research Of Micromachined Gyroscope Based On Polysilicon Nanofilms

The micro-machined gyroscope is an important inertial device in field of microelectronics mechanical systems. By analyzing the working principle and the structural characteristic of the gyroscope at home and abroad, this paper chooses the fold-type orthogonal beam and designs the micro-machined gyroscope based on polysilicon nanofilms. And aiming at consumer electronic field, the paper sets up a series of parameters of the gyroscope.Firstly, the paper determines the comb drive mode under the principle of the electrostatic drive, analyzes the relationship of the detection frequency, the driving frequency, the sensitivity and the working bandwidth based on the dynamics. And using the characteristics of the high strain factor polysilicon nanofilms and the small temperature coefficient resistance, the paper designs the polysilicon nanofilms sensitive resistance,and determines the size that 21μm×30μm(length×width) for the strain resistance through the calculating. Secondly, using the finite element simulation analysis, the paper models and optimizes the angular velocity sensitive structure, and gives the final device size in combination with requirements of the microelectronics technology. By using the modal analysis, the paper obtains vibration mode and fixed frequency of ten orders, which the driving mode frequency is 4536 Hz, the detection modal frequency is 4385 Hz, its working bandwidth of 86 Hz; In the overload capacity analysis simulation, the paper gets the driving direction overload capacity of the device that is 695 g, and detection direction impact resistant capacity that is 890g; In the path analysis, the paper gets the largest strain position on both ends of the beam, obtains the larger sensitivity, which the strain resistance is placed in the detection beam at the 20μm and quality piece side at 19μm; Conbining the damping analysis of driving direction and detecting direction,the paper obtains the driving direction and the detecting direction of the quality factor that is respectively 3035, 606; Finally, through Coriolis force analysis,get device under normal working range(-500 °/ s~500 °/s), the simulation results get the full scale output voltage that is 55 mV, the sensitivity that is 111μV/°/s, and the maximum angular velocity of the measurable range for-1250°/s ~ 1250 °/s.This paper designs the gyroscope based on the polysilicon nanofilms, Structure size set to make all kinds of performance parameters achieve the expected design target. In addition, the article based on the conventional silicon technology, MEMS surface process and body the gyroscope of the structure of the technological process is given. For the landscape design and manufacturing process provides certain theory basis.