Recent progress on magnetic sensors with nanostructures and applications
- Electrotechnical Lab., Tsukuba (Japan)
Hall devices and magnetoresistors totaling a billion per year made of semiconductors are used for displacement sensors of brushless motors in a videotape recorder and disk driver, contactless switches, and bill detectors of vending machine. Conventional magnetic sensors typically have a 100-{mu}m active region and 1 {mu}m thickness. Two kinds of new magnetic sensors with high sensitivity and high resolution are presented. A semiconductor Hall device made of pseudomorphic InAlAs/InGaAs heterostructures with a high electron mobility of 16 000 and 160 000 cm{sup 2}/Vs, respectively, at 300 and 10 K can be operated in a wide temperature range. A 200-{mu}m-square Hall device with a low impedance of 310 {Omega} and a very thin active layer of 10 nm has a large product sensitivity of 320 V/A T and a maximum magnetic sensitivity of 15 V/T at room temperature. The magnetic sensitivity for current drive increases with decreasing temperature but is constant below liquid-nitrogen temperature. It is expected that the quantum-well Hall device with low dimensional heterostructure has a nanoscale resolution with a high signal-to-noise ratio. Second, a vacuum magnetic sensor with a comb-shaped field emitter, gate, and a pair of splitted collectors is presented. The principle of operation is based on the galvanomagnetic effect in vacuum. The device has a higher magnetic sensitivity of 1000%/T compared with semiconductor sensors. 25 refs., 16 figs., 3 tabs.
- OSTI ID:
- 136149
- Journal Information:
- Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena, Vol. 13, Issue 3; Other Information: PBD: May-Jun 1995
- Country of Publication:
- United States
- Language:
- English
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