Integrative Biology

Biography

Biography: Daisuke Yamane

Abstract

MEMS (microelectromechanical systems) technology has enabled micro-scaled capacitive accelerometers to be widely available in consumer electronics for the sensing range to be mostly above 1 G (9.8 m/s2). In recent years, accurate sensing of low acceleration, specifically below 1 G (9.8 m/s2), has been one of the major interests for MEMS accelerometers to be used for applications such as human-activities monitoring or the integrated inertial measurement unit. The commercialized MEMS accelerometers exhibit, however, insufficient performance for sub-1G sensing due to the mechanical noise that determines the sensitivity of the sensor. The mechanical noise is dominated by Brownian noise (BN), and BN is inversely proportional to the proof mass where silicon is used as the material in most MEMS accelerometers; the physical dimension of the silicon proof mass constrains the minimum level of BN, which is typically in the range from 100 to 1000 microG/Hz1/2. For the reduction of the BN on micro-scale accelerometers, we have employed gold as a material of the proof mass. Owing to the high density of gold, the BN can easily be an order of magnitude smaller than that of silicon proof mass. Moreover, the MEMS sensor can be made by a post-CMOS (complementary metal-oxide semiconductor) process using gold electroplating. The post-CMOS process can also help to shrink the device footprint by implementing the MEMS structures onto the sensing CMOS circuitry. By utilizing the above approaches, the developed MEMS capacitive sensor showed the BN to be less than 1 microG/Hz1/2. The proposed MEMS accelerometers can be of great use to a wide variety of technologies that need to sense micro-motion, and highly-sensitive monitoring of body movements will shed light on the medical and healthcare application.