Three-axis magnetic field sensor

Abstract

The three bridge circuits (101, 111, 121) each include magnetoresistive sensors coupled into a Wheatstone bridge (100) to sense magnetic fields (160) in three orthogonal directions (110, 120, 130). ), which are set by a single pinning material deposition and bulk wafer setting process. One (121) of the three bridge circuits includes a first magnetoresistive sensor (141) comprising: a first sensing element (122) disposed on the pinning layer (126), the first sensing element (122 ) having first and second edges and first and second faces; and a first flux guide (132) disposed non-parallel to the first face of the substrate and having a proximity to the first sensing element (122) The first edge of and the end of the first face. An optional second flux guide (136) may be disposed non-parallel to the first face of the substrate and have an end proximate to a second edge of the first sensing element (122) and the second face.

Description

technical field [0001] The present invention relates generally to the field of magnetoelectronic devices, and more particularly to CMOS compatible magnetoelectronic field sensors for sensing magnetic fields in three orthogonal directions. Background technique [0002] Sensors are widely used in modern systems to measure or detect physical parameters such as position, motion, force, acceleration, temperature, pressure, etc. Although there are many different sensor types for measuring these and other parameters, they all suffer from various limitations. For example, inexpensive low-field sensors such as those used in electronic compasses and other similar magnetic sensing applications often include anisotropic magnetoresistance (AMR) based devices. In order to achieve the required sensitivity and a reasonable resistance that works well with CMOS, the sensing cells of these sensors are usually on the order of square millimeters in size. For mobile applications, AMR sensor con...

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Problems solved by technology

Since the dimensions of vertically bonded chips are typically dictated by pad pitches determined according to processing constraints, this technique results in a large vertical extent

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