(Invited) CMOS-MEMS Based Microgravity Sensor and Its Application

Abstract

This paper reviews the feature of newly developed CMOS-MEMS (microelectromechanical systems) and MEMS accelerometers and its application for a diagnosis of Parkinson’s disease. In order to realize micro-G (1G=9.8m/s2) level sensing, we propose and develop capacitive MEMS accelerometers with Au proof mass using the multi-layer metal technology. In order to reduce Brownian noise (BN), which determines the sensitivity of MEMS accelerometer, we utilize Au as a high density proof mass. In addition, we investigate the crystal structure of Au in terms of the device reliability. Furthermore, we demonstrate the validity of applying the MEMS accelerometer for the early-stage diagnosis of Parkinson’s disease. The experimental results regarding the sensor, the material and the diagnosis suggest that our microgravity sensor can pave the new way for the early-stage diagnosis of Parkinson’s disease.

Effective Young’s Modulus of Complex Three Dimensional Multilayered Ti/Au Micro-Cantilevers Fabricated by Electrodeposition and the Temperature Dependency

“…Size reduction and performance enhancement of micro-electromechanical systems (MEMS) devices are always challenging and important research interests, especially for MEMS devices, such as MEMS accelerometers commonly equipped in smartphones. Recently, the application of MEMS accelerometers for biomedical applications has been proposed [1][2][3]. Detection of body tremors [3] and muscular sounds [4] has been reported using a highly sensitivity MEMS accelerometer.…”

“…Recently, the application of MEMS accelerometers for biomedical applications has been proposed [1][2][3]. Detection of body tremors [3] and muscular sounds [4] has been reported using a highly sensitivity MEMS accelerometer. Early detection of neurological intractable diseases such as Parkinson's diseases would be possible by analyzing information obtained from the body tremors and muscular sounds.…”

“…Precious metal materials have excellent properties, such as high chemical stability, electrical conductivity, and biocompatibility, and are advantageous toward electronic devices [5]. Recently, the application of gold-based materials to MEMS devices has received a great amount of attention, and MEMS accelerometers employing gold components prepared by electrodeposition are reported to have a small size whiling retaining high sensitivity [2,3], which is mainly contributed by gold's high mass density (19.3 × 10 3 kg/m 3 at 298 K [6]). The acceleration sensing unit used for accelerometers is G (1 G ≈ 9.8 m/s 2 ).…”

“…The acceleration sensing unit used for accelerometers is G (1 G ≈ 9.8 m/s 2 ). The sensing ability of a gold-based MEMS accelerometer is reported to reach µG level and the Brownian noise is merely 22 nG/ √ Hz [3]. On the other hand, gold is known to be a relatively soft metallic material among materials commonly utilized in electronics, and electrodeposition is a powerful method to strengthening the gold by grain refinement [7,8] alloying [9][10][11] and introduction of nanotwins [12].…”

Co-Electrodeposition of Au–TiO2 Nanocomposite and the Micro-Mechanical Properties

“…Electrodeposition methods are widely applied in fabrication of micro-components used in miniaturized electronic devices such as microelectromechanical system (MEMS) devices. For instance, the proof mass and micro-springs in a highly-sensitive MEMS accelerometers are prepared by Au electrodeposition [1,2]. Au is used here because performance of a MEMS accelerometer is highly dependent on overall mass of the movable components, while miniaturization of the component is also required.…”