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Semiconductor
Materials for Magnetic Sensors |
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Murata magnetic
sensors use magnetoresistive elements made of n-InSb (compound
semiconductor of the III-V group). |
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| Material property |
InSb |
InAs |
GaAs |
Ge |
Si |
| Crystalline structure |
Concentrated zinc ore |
Concentrated zinc ore |
Concentrated zinc ore |
Diamond |
Diamond |
| Band gap (eV) |
0.17 |
0.36 |
1.43 |
0.66 |
1.12 |
| Electron mobility (cm2/V s) |
78000 |
33000 |
8500 |
3900 |
1900 |
| Hole mobility (cm2/V s) |
750 |
450 |
450 |
1900 |
425 |
| Melting point (°C) |
525 |
943 |
1237 |
953 |
1420 |
| Density (Kg/m3) |
5.775 |
5.67 |
5.316 |
5.35 |
2.3 |
| Lattice constant (Å) |
6.48 |
6.06 |
5.64 |
5.66 |
5.43 |
| Resistivity (ohm cm) |
5 x 10-3 |
3.1 x 10-1 |
3.8 x 108 |
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- n-InSb materials with high electron mobility are used
for the magnetoresistive elements.
- InAs, GaAs, Ge, Si, and InSb materials are used for
the Hall elements and Hall ICs.
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Structure
of the Magnetoresistive Element |
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The
magnetoresistive element has two terminals. The element for practical
use is formed like meanders by means of photolithography, so that it
has multiple electrodes on the semiconductor surface to provide high
resistance and high output. |
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 Element Model (meander-formed element) |
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- By modifying the shape of the element, a wide range
of resistances can be achieved.
- An element is formed on a magnetic or non-magnetic
substrate, depending on its usage. If the priority is high output, a
magnetic substrate is used. If the priority is immunity to external
magnetic noise, a non-magnetic substrate is used.
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