Show/Hide Menu
Hide/Show Apps
Logout
Türkçe
Türkçe
Search
Search
Login
Login
OpenMETU
OpenMETU
About
About
Open Science Policy
Open Science Policy
Open Access Guideline
Open Access Guideline
Postgraduate Thesis Guideline
Postgraduate Thesis Guideline
Communities & Collections
Communities & Collections
Help
Help
Frequently Asked Questions
Frequently Asked Questions
Guides
Guides
Thesis submission
Thesis submission
MS without thesis term project submission
MS without thesis term project submission
Publication submission with DOI
Publication submission with DOI
Publication submission
Publication submission
Supporting Information
Supporting Information
General Information
General Information
Copyright, Embargo and License
Copyright, Embargo and License
Contact us
Contact us
A low-drift silicon MEMS resonant accelerometer
Download
index.pdf
Date
2023-1-23
Author
Gavcar, Hasan Doğan
Metadata
Show full item record
This work is licensed under a
Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License
.
Item Usage Stats
392
views
0
downloads
Cite This
This thesis presents the design, fabrication, and experimental verification of low temperature drift silicon resonant accelerometers for tactical grade applications. The working principle of a silicon resonant accelerometer is based on force sensing, in which the sensor output is a frequency proportional to the input acceleration. The stress-insensitive sensor design prevents the thermal stress produced by the mismatch of the thermal expansion coefficients (CTE) of glass and silicon from transmitting to the DETF resonators. In the scope of this thesis, three different silicon resonant accelerometer structures are sequentially designed, fabricated, characterized, and tested with the frequency readout circuit. The first sensor structure consists of two differential DETF resonators and a large proof mass connected to a stationary outer frame. The second sensor structure utilizes microlevers to magnify the inertial force acting on the DETF resonators in addition to the sensor frame of the first sensor structure. Although specially designed stress release beams are implemented in the first and second sensor structures, they suffer from thermal stress caused by the stationary outer frame after fabrication. In the third sensor design, the sensor structure is placed on a specially designed single anchor to overcome the stress problem encountered in the first two sensor designs. The FEM simulations are performed to analyze and optimize the mode shapes, force sensitivity, and temperature sensitivity of the sensor structures. The designed resonant accelerometers are fabricated using the aMEMS1 process with wafer-level hermetic encapsulation. The fabricated sensor chips are integrated with the capacitive preamplifier and digital signal processor (DSP)-based phase-locked-loop (PLL) system implemented on a Zurich Instrument HF-2 lock-in amplifier. The functionalities of the accelerometers are verified by the resonance and 4-point tumble tests, and their performances are experimentally evaluated in terms of thermal sensitivity and bias stability by temperature and Allan variance tests. Test results show that the single-anchor silicon resonant accelerometer achieves a bias instability of 1.25 µg, a bias stability of 2.8 µg, a bias repeatability of 6.6 µg, a velocity random walk of 6.1 µg/√Hz for the sensor bandwidth of 33 Hz at room temperature, and a maximum bias change of 4.3 mg for the temperature range from -40 °C to +85 °C. It has a measurement range up to ±60 g with a 500-ppm deviation from the linear scale range. Compared to the commercial capacitive MEMS accelerometer developed by Mikrosistemler, the silicon resonant accelerometer developed in this work exhibits at least a 20-fold improvement in bias temperature sensitivity, a 7-fold improvement in bias instability, a 112-fold improvement in bias stability, and a 2-fold improvement in noise floor. More importantly, although the bias of the commercial capacitive MEMS accelerometer tested in this study moves 1.7 mg in 50 minutes at constant 25°C, the bias of the silicon resonant accelerometer shifts less than 0.25 mg in 10 hours at ambient temperature.
Subject Keywords
MEMS
,
Resonant accelerometer
,
Bias drift
,
Temperature sensitivity
URI
https://hdl.handle.net/11511/102527
Collections
Graduate School of Natural and Applied Sciences, Thesis
Suggestions
OpenMETU
Core
A single mass two-axis capacitive MEMS accelerometer with force rebalance
Köse, Talha; Terzioʇlu, Yunus; Azgın, Kıvanç; Akın, Tayfun (2015-03-26)
This paper presents a single mass 2-axis MEMS capacitive accelerometer with a unique force rebalance method achieved with the readout circuit developed for the simultaneous 2-axis acceleration sensing. Using a single mass structure with extra fingers for reading multiple axes allows better sensor performances when compared to multi-axis accelerometers with individual proof masses occupying the same die area. Test results show 274 mV/g scale factor for x-axis, and 280 mV/g scale factor for y-axis, while the ...
AN AUTOMATIC ACCELERATION COMPENSATION SYSTEM FOR A SINGLE-MASS MEMS GYROSCOPE
Gavcar, H. D.; Azgın, Kıvanç; Alper, S. E.; Akın, Tayfun (2015-06-25)
This paper presents the architecture and experimental verification of an automatic acceleration compensation system applied to a single-mass MEMS gyroscope. The proposed method eliminates low frequency proof mass motion of the gyroscope due to external accelerations, suppressing the g-sensitivity of the gyroscope bias up to 12 times. This is achieved by dedicated acceleration cancellation electrodes ( ACEs) for the first time in the literature, eliminating any degradation of the sensor bias stability and no...
A low-power robust humidity sensor in a standard CMOS process
Okcan, Burak; Akın, Tayfun (2007-11-01)
This paper presents a low-cost thermal-conductivity-based humidity sensor implemented using a 0.6-mu m CMOS process, where suspended p-n junction diodes are used as the humidity-sensitive elements. The measurement method uses the difference between the thermal conductivities of air and water vapor at high temperatures by comparing the output voltages of two hea ted and thermally isolated diodes; one of which is exposed to the environment and has a humidity-dependent thermal conductance, while the other is s...
A single-mass self-resonating closed-loop capacitive MEMS accelerometer
Kose, Talha; Terzioglu, Yunus; Azgın, Kıvanç; Akın, Tayfun (2016-11-02)
This paper presents a single-axis, self-resonating accelerometer. The presented accelerometer incorporates a resonating sensing element which is used along with a closed-loop self-resonance circuit, and the analog force-feedback readout circuit. During operation, the sensing element is oscillated at its fundamental frequency through dedicated actuation electrodes in closed-loop configuration. This oscillation is used to modulate the capacitance difference between another set of differential electrodes which...
A high performance automatic mode-matched MEMS gyroscope with an improved thermal stability of the scale factor
Sonmezoglu, S.; Alper, S.E.; Akın, Tayfun (2013-06-20)
This paper presents a high performance, automatic mode-matched, single-mass, and fully-decoupled MEMS gyroscope with improved scale factor stability. The mode-matching system automatically achieves and maintains the matching between the drive and sense mode resonance frequencies with the help of dedicated frequency tuning electrodes (FTEs). This method isolates the drive and sense mode frequency response dynamics by keeping the proof mass voltage (V PM ) constant, improving the scale factor stability up to ...
Citation Formats
IEEE
ACM
APA
CHICAGO
MLA
BibTeX
H. D. Gavcar, “A low-drift silicon MEMS resonant accelerometer,” Ph.D. - Doctoral Program, Middle East Technical University, 2023.