2005 Fiscal Year Final Research Report Summary
Study on the principle and experiments on the extremely downsized magnetic field sensor and application to MEMS.
| Project/Area Number |
16560319
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Electron device/Electronic equipment
|
|---|
| Research Institution | Salesian Polytechnic |
|---|
Principal Investigator |
YOSIZAWA Nobuyuki Salesian Polytechnic, Electronic Engineering Dept., Prof., 教授 (50106134)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
SHIMADA Yutaka Tohoku University, Graduate School of Engineering, Visiting Professor, 大学院・工学研究科, 客員教授 (00006157)
|
|---|
| Project Period (FY) |
2004 – 2005
|
| Keywords | magnetic field sensor / quartz resonator / magnetoelastic effect / amorphous ribbon |
|---|
| Research Abstract |
Development of downsizing technology for magnetic field sensors is essential for direction sensing in the IT mobile communication devices. The advantage of the sensor studied in this project is that it senses magnetic field in terms of frequency sift of magnetomechanical vibration, namely, FM (frequency modulation) is adopted in contrast to AM for the conventional sensors such as MI, fluxgate, or Hall elements. The sensor is a composite made of a crystal oscillator and highly magnetostrictive ferromagnetic layers with high sensitivity to magnetic field. For ferromagnetic layers amorphous ribbons (Fe-Si-B) and thin films of Fe-Co-Zr sputtered films were used. The composite of crystal oscillator and amorphous ribbons exhibit high sensitivity which is high enough as an earth field sensor. In case of thin films directional difference of thermal expansion coefficient in the crystal plane (18.5 X-cut) caused very high magnetic anisotropy in the film. This means search for the crystal plane with low anisotropic thermal expansion is needed. However, Si is a basic material in the MEMS technology and use of thin films is possible. Furthermore, for a very small Si reed Q factor of mechanical vibration is very high and can stand for crystal oscillators. In our experiment Si reeds with the size (500×60μm, t = 10μm) were formed in a Si wafer and sift of resonance vibration frequency was detected in a magnetic field. Although the sensitivity is not high, this experiment verified that extremely downsized sensors are possible using the MEMS technology.
|
