Magnetic field sensor

Abstract

The invention relates to a magnetic field sensor comprising a substrate having a first side (S1). The substrate comprises at the first side (S1) a silicon comprising semiconductor layer (P-SUB) which comprises a buried N-well (DNW). A bipolar transistor having an emitter region (PE+, NE+), a base region (PB+, NB+), and a first collector region (CLR1) and a second collector region, is provided in the silicon comprising semiconductor layer (P-SUB). The emitter region (PE+, NE+) is located at the first side (S1) above the buried N-well (DNW). According to the invention the bipolar transistor is arranged such that, in operation, a part of an emitter current (IEM) that traverses the base region (PB+, NB+) is distributed over the first and second collector regions (CLR1, CLR2) obtaining a first and a second collector current (ICL1, ICL2), wherein a difference between the first and second collector currents (ICL1, ICL2) is determined by a magnetic field component (B x, B z ) perpendicular to a current plane. A bipolar magneto-transistor structure is obtained which is compatible with triple-well technology and that is sensitive to magnetic fields in a direction perpendicular to the current plane. The magnetic field sensor is compatible with triple-well technology and has a high linearity and a high sensitivity. The invention further relates to an integrated circuit comprising such magnetic field sensor (Snsr) and a card provided with such integrated circuit.

Description

technical field [0001] The invention relates to a magnetic field sensor, an integrated circuit comprising such a magnetic field sensor and a card comprising such an integrated circuit. Background technique [0002] There are many solutions for magnetic field detection in silicon integrated circuits, such as known Hall plates with integrated amplifiers, magnetotransistors (JFETs or MOSFETs) of bipolar or unipolar nature, magnetoresistors and magnetodiodes. [0003] US2005 / 0230770 discloses a vertical Hall element comprising: a substrate; a semiconductor region having a first conductivity type and disposed in the substrate; and a magnetic field detection portion disposed in the semiconductor region. The magnetic field detection portion can detect a magnetic field parallel to the surface of the substrate in a case where a current flows through the magnetic field detection portion in a vertical direction of the substrate. The semiconductor region is a diffusion layer comprising...

AI Technical Summary

Problems solved by technology

[0006] As can be understood from the above, known magnetic field sensors, depending on the chosen solution, suffer from various disadvantages such as low sensitivity, low linearity, incompatibility with conventional baseline CMOS technology (usually triple-well technology) (due to the need for additional processing steps)

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