Development of an integrated resonant MEMS temperature sensor

Download
index.pdf
2016
Köse, Talha
Show full item record
206
views
111
downloads
This thesis presents the design, fabrication and characterization of a high performance, integrated, resonant MEMS temperature sensor, and temperature compensation of a capacitive MEMS accelerometer. Two different double-ended-tuning-fork (DETF) type resonator designs are developed and characterized for temperature sensing. The strain-amplifying beam structure is added to the DETF resonators in order to enhance thermal strain induced on the DETF tines due to the different thermal expansion coefficients of the substrate and the sensor structure. Two different supplementary temperature sensor designs have been demonstrated in order to compare the effectiveness of the strain-amplifying beam, i.e., the doubly-clamped DETF resonators, and one-end-free DETF resonators. Two DETF resonators with different geometric properties have been used in the temperature sensor designs in order to verify analytical equations representing the operation of DETF resonators as temperature sensors. Finite Element Analysis simulations (modal and thermo-mechanical) have been conducted for each of the temperature sensor designs. To realize real-time data acquisition from the temperature sensors, a read-out circuit which sustains self-resonance of the DETF resonators has been designed and demonstrated with the circuit simulations. The co-fabrication of the MEMS temperature sensors and MEMS accelerometer have been demonstrated by on-chip integration of the devices. This integration enables precise temperature measurements by removing the thermal lag between the temperature sensor and the MEMS accelerometer to be temperature-compensated. After fabrication, characterization tests have pointed out a good vacuum environment (pressure inside the sensor dies in range of 10-100 mTorr) which corresponds to quality factors in the order of 10000. The system-level temperature tests (from -20 °C to 60 °C) are done while the accelerometer and two temperature sensors were simultaneously operated in closed-loop. Temperature coefficient of frequency values (TCf) of 730 ppm/K and 636 ppm/K have been achieved with the proposed temperature design, which reveals an improvement in sensitivity (TCf) up to 2.4 times when compared to doubly-clamped DETF resonators, and an improvement up to 35 times improvement when compared to the one-end-free DETF resonators. Minimum detectable temperature attained with the proposed temperature sensor designs has been reported as 1.1 mK. The temperature compensation of MEMS accelerometer has resulted in an improvement up to 830 times by reducing the temperature dependence of the accelerometer output from 1164 µg/°C to 1.4 µg/°C. The noise performances of the MEMS accelerometers used in this study points out bias instability of 10 µg up to integration time of 100 seconds, and the velocity random walk of 13 µg/√Hz.
Microelectromechanical systems., Electromechanical devices., Accelerometers., Resonators.
http://etd.lib.metu.edu.tr/upload/12619746/index.pdf
https://hdl.handle.net/11511/25439
Graduate School of Natural and Applied Sciences, Thesis

Suggestions

Development of electrochemical etch-stop techniques for integrated MEMS sensors
Yaşınok, Gözde Ceren; Akın, Tayfun; Department of Electrical and Electronics Engineering (2006)
This thesis presents the development of electrochemical etch-stop techniques (ECES) to achieve high precision 3-dimensional integrated MEMS sensors with wet anisotropic etching by applying proper voltages to various regions in silicon. The anisotropic etchant is selected as tetra methyl ammonium hydroxide, TMAH, considering its high silicon etch rate, selectivity towards SiO2, and CMOS compatibility, especially during front-side etching of the chip/wafer. A number of parameters affecting the etching are inv...
A Versatile 5th order sigma-delta modulation circuit for MEMS capacitive accelerometer characterization /
Asgarli, Tunjar; Akın, Tayfun; Department of Electrical and Electronics Engineering (2014)
With the significant developments in capacitive MEMS inertial sensors, tons of studies in the literature trying to enhance the performance parameters of MEMS capacitive accelerometer systems such as linearity, noise floor and bandwidth further has emerged. However, all the studies are conducted on a certain reference point, which is mainly the properties of the accelerometer sensor that alter a lot in the design of the high performance interface readout circuit. The designed interface circuits usually adopt...
Development of a resonant mass sensor for MEMS based cell detection applications
Eroğlu, Deniz; Külah, Haluk; Department of Electrical and Electronics Engineering (2012)
This thesis reports design and implementation of a MEMS based resonant mass sensor for cell detection applications. The main objective of the thesis is the real-time detection of captured cells inside liquid medium and obtaining the detection results by electronic means, without the aid of any external optical instruments. A new resonant mass sensor architecture is presented that has various advantages over its conventional counterparts. The device oscillates in the lateral direction, eliminating squeeze fi...
Development of resonant mass sensors for MEMS based real time cell detection applications
Kangül, Mustafa; Külah, Haluk; Department of Electrical and Electronics Engineering (2015)
This thesis represents design and implementation of MEMS based resonant mass sensors for cell detection applications. The main objective of the thesis is real-time detection inside liquid medium and obtaining the results by electronic means, without the assistance of bulky optical instruments. Novel resonant based mass sensor architectures that have various improvements over selected benchmark design are presented. Purpose of the new structures is to establish real-time mass detection by improving the quali...
Compensation methos for quasi-static acceleration sensitivity of MEMS gyroscopes /
Gavcar, Hasan Doğan; Azgın, Kıvanç; Department of Electrical and Electronics Engineering (2014)
This thesis presents the quasi-static acceleration compensation methods for a fully decoupled MEMS gyroscope. These methods are based on the utilization of the amplitude difference information between the residual quadrature signals on the differential sense mode electrodes to sense the static acceleration acting on the sense mode of the gyroscope. There are three different quasi-static acceleration compensation methods presented in this thesis. In the first method, the static acceleration is measured by co...
Citation Formats
T. Köse, “Development of an integrated resonant MEMS temperature sensor,” M.S. - Master of Science, Middle East Technical University, 2016.
METU IIS - Integrated Information Service open@metu.edu.tr