Magnetic sensor formed on semiconductor substrate

Abstract

Planar magnetic sensor, made in particular via CMOS techniques on a semiconductor substrate (1) of for example parallelepiped shape. It includes an amorphous ferromagnetic core (10) in the shape of a Greek cross which occupies the two diagonals of the square defined by the outer contour (90) of the excitation coil (9), the latter being made in the form of a planar winding of square shape. One thus measures, via flat detection coils (70, 80 and 71, 81) which are mounted in series and in a differential arrangement, the two orthogonal components (H1, H2) of the external magnetic field (Hext).

Description

technical field [0001] The present invention relates to a substantially planar magnetic sensor, especially fabricated on an integrated circuit, of the magnetic fluxer type and generally intended to be assembled for detecting magnetic forces of very low values ​​in a plane meter, such as in medical applications. The magnetometer is preferably fabricated using a CMOS process and its associated circuitry is integrated on the substrate on which the sensor is fabricated. Background technique [0002] The publication "Integrated Planar Fluxgate Sensor" by Messrs. L. Chiesi, J.A. Flaganan, B. Jannosy, and R.S. Poponic of the Swiss Federal Institute of Technology of Lausanne (Switzerland) presented at the "Euro Sensors X1" conference in Poland in 1997 can be cited. With Amorphous Metal Core" cited as the state of the art. [0003] This publication describes a planar magnetic microsensor integrated on a silicon substrate, shown in Figure 1 as an illustration of the prior art. [0...

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Problems solved by technology

[0009] This known device has disadvantages, on the one hand, the inability to detect the external magnetic field Hext along two orthogonal directions without changing the relative position of the sensor, and on the other hand, the lack of sensitivity

Furthermore its output voltage depends on the frequency of the excitation current and the current consumption is relatively high

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