Title :
Pure oxide structure for temperature stabilization and performance enhancement of CMOS-MEMS accelerometer
Author :
Liu, Yu-Chia ; Tsai, Ming-Han ; Fang, Weileun
Author_Institution :
Inst. of NanoEngineering & Microsyst., Nat. Tsing Hua Univ., Hsinchu, Taiwan
fDate :
Jan. 29 2012-Feb. 2 2012
Abstract :
In this study, the stacking of pure oxide layers as the mechanical structures for CMOS-MEMS accelerometer has been developed and demonstrated for the first time. Thus, the distribution of metal-oxide composites in CMOS-MEMS accelerometer is changed from area to line. Such design has the following advantages: (1) the initial deformation of suspended MEMS structures due to the residual stresses of metal-oxide films is reduced, (2) the thermal deformation of suspended MEMS structures due to the thermal expansion coefficient (CTE) mismatch of metal-oxide films is also suppressed, and (3) the parasitic capacitance of sensing electrodes routing underneath the proof-mass can be further reduced. Thus, the accelerometer has higher sensitivity with less thermal drift. Compare with the existing metal-oxide composites accelerometer, the pure oxide accelerometer increases sensitivity of 7-fold, and decreases the structure-deformation (measured by radius-of-curvature (ROC) of proof-mass) of 2.1-fold (by residual stresses) and 2.4-fold (by temperature change). Moreover, the noise floor reduced 4.7-fold.
Keywords :
CMOS integrated circuits; accelerometers; deformation; internal stresses; microsensors; thermal expansion; CMOS-MEMS accelerometer; mechanical structures; metal-oxide composites; metal-oxide films; noise floor; performance enhancement; pure oxide accelerometer; radius-of-curvature; residual stresses; sensing electrodes; suspended MEMS structures; temperature stabilization; thermal deformation; thermal drift; thermal expansion coefficient; Accelerometers; CMOS integrated circuits; Electrodes; Metals; Micromechanical devices; Sensors; Temperature measurement;
Conference_Titel :
Micro Electro Mechanical Systems (MEMS), 2012 IEEE 25th International Conference on
Conference_Location :
Paris
Print_ISBN :
978-1-4673-0324-8
DOI :
10.1109/MEMSYS.2012.6170244