Activities of the G-device Project
Under the guidance of Ryutaro Maeda, director of theResearch Center for Ubiquitous MEMS and Micro Engineering(UMEMSME) under the National Institute of Advanced
Industrial Science and Technology (AIST), G-device Center
Kansai (center director Susumu Sugiyama) was established atRitsumeikan University as a NEDO-sponsored project. The
Center conducts joint research with Kyoto University andcollaborates with four companies in MEMS-related industries,
while aggressively promoting the project’s development.
One of the most important activities implemented by theMinistry of Economy, Trade and Industry (METI) in its efforts
to promote new growth strategies is “green innovation.” Steps
necessary for realizing green innovation include determining
how to conserve resources in the manufacturing processes
themselves by utilizing innovative next-generation devices anddetermining how to reduce environmental impact byimplementing more efficient manufacturing processes. To thisend, G-device Center Kansai is conducting R&D on highperformance MEMS sensors and developing a network systemwith these sensors in order to demonstrate that clean rooms
used in MEMS fabrication can be made eco-friendly. Thefollowing is a detailed description of activities conducted in theG-device Project.

server through wireless communications. While a battery isused for powering circuits in this project, we hope to develop a
self-reliant high-performance sensor module employing avibration-based power generator or a wireless power supply
system, for example. Each sensor module will be contained in a
30x30x10mm package and used as a network node in thesystem. One of the major objectives in developing sensor
modules has been to create a concept of low power
consumption in order to construct network nodes employing
battery-free, self-reliant wireless sensors. To this end, we will
study principle models for optimizing the sensor sampling rate,
number of sensing categories, wireless data transfer rate,
wireless communication protocol, and AD conversion rate in thesignal processing circuit, with consideration for designing thesensor to be ultra-small, inexpensive, and highly sensitive.

3) Contaminant Gas Sensors
Currently clean rooms waste a lot of energy in draft
ventilation because clean air is also being exhausted. Energy
consumed when exhausting clean air can be reduced throughreal-time monitoring of fluctuations in contaminant gas.
Specifically, the Center will develop MEMS sensors using ametal oxide semiconductor material, such as tungsten trioxide(WO3) to produce a self-reliant, energy-efficient gas sensor for
detecting ammonia (NH3) and other inorganic gases.

1) Development of a Sensor Network System
G-device Center Kansai is developing a wireless sensor
network system configured of wireless MEMS sensors. The
system is designed to allow a flexible layout of sensor nodes andto monitor multiple environmental conditions.
The Center will identify system requirements for acquiring
detailed measurements at multiple points aimed at maintaining
a consistent environmental quality and requirements for energy
conservation control and will conduct basic and component
studies of the control system. Plans call for experimental
demonstrations to be conducted in a new MEMS clean room
established at AIST Tsukuba East. The effectiveness of thesystem design will be verified through controlled operations andvisual control of temperature, humidity, and particles, with thegoal of reducing CO2 emissions from energy use in clean rooms
to 60% of 1990 levels.

4) Principles of Sensor Node Localization
While it will be important to develop an on-demand multipoint sensor network system capable of discovering thedistribution of particulate in a clean room in real-time, today
particle sensors are too expensive to equip a system with thenumber needed to achieve sufficient results. Therefore, theCenter is working on an alternate method of developing
principles of localization for wirelessly powered sensors thatcan be attached to workers’ shoes, for example.

5) Functional Thin Films for Sensitive TemperatureSensing
The sensor network will require highly sensitive
temperature sensors for determining the distribution of bodytemperatures and equipment temperatures over time, and selfreliant power-generating devices to implement a wirelessnetwork. In order to improve the performance and functionalityof the temperature sensors, we will work to develop materials(including lead-free materials) and processes for forming
functional thin films with pyroelectric/piezoelectric properties.

2) Development of High-Performance Sensor
Modules
The Center will also study sensor node platforms for asensor network system comprising high-performance sensor
modules arranged at multiple points.
The network system is provided with sensors for monitoring
temperature, humidity, pressure, acceleration, and otherconditions, with the sensors designed in the form of replaceable
modules in order that the system may be adapted to different
applications. Each module is configured of a sensor unit,battery, signal-processing circuit, wireless transmitting circuit,and antenna. With this construction, the module has functions
for sensing ambient conditions influencing the air quality in aclean room, such as temperature, humidity, airflow,acceleration, and pressure, acquiring a signal from the sensor,and converting the signal to data that can be exchanged with a6) Development of Environmentally Friendly
Processes for Polymer Sensor Integration
We are developing polymer sensors with biocompatibility(superior hemocompatibility) using polymer processes that aresuperior to the conventional silicon processes in exploiting thespecific functions of bio/organic materials such as syntheticorganic molecules and biomolecules. More specifically, theCenter is manufacturing MEMS actuator prototypes (mirrordevices) and evaluating their reflectance and surface roughness
properties.

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