Integrated three-dimensional magnetic sensing device and method to fabricate an integrated three-dimensional magnetic sensing device

An integrated three-dimensional magnetic sensing device comprising:

• a monolithic substrate defining (i) a plane of the sensing device, (ii) a first surface parallel to the plane, and (iii) second and third surfaces sloped with respect to the first surface;
• a first magnetic sensor formed at the first surface for producing a first output signal that represents a magnetic field component in a first direction, wherein the first direction is substantially parallel to the plane;
• a second magnetic sensor formed at the first surface for producing a second output signal that represents a magnetic field component in a second direction, wherein the second direction is substantially parallel to the plane and wherein the second direction is substantially orthogonal to the first direction;
• and
• a third magnetic sensor formed at least in part on the second and third surfaces for producing a third output signal that represents a magnetic field component in a third direction, wherein the third direction is substantially orthogonal to the first surface.

A method of fabricating an integrated three-dimensional magnetic sensing device, the method comprising:

• forming a first magnetic sensor unit on a first surface area of a single substrate, wherein forming the first magnetic sensor unit comprises depositing a first set of magnetoresistive strips on the first surface area and depositing a first set of conductive straps on the first set of magnetoresistive strips:
• forming a second magnetic sensor unit on a second surface area of the single substrate, wherein forming the second magnetic sensor unit comprises depositing a second set of magnetoresistive strips on the second surface area and depositing a second set of conductive straps on the second set of magnetoresistive strips;
• etching the single substrate to form at least one sloped surface, wherein the at least one sloped surface is sloped with respect to the first and second surface areas,
• forming a third magnetic sensor unit on the at least one sloped surface of the single substrate, wherein forming the third magnetic sensor unit comprises depositing a third set of magnetoresistive strips on the at least one sloped surface and depositing a third set of conductive straps on the third set of magnetoresistive strips;
• coupling interconnections to the first set of magnetoresistive strips to form a first resistor bridge network;
• coupling interconnections to the second set of magnetoresistive strips to form a second resistor bridge network;
• coupling interconnections to the third set of magnetoresistive strips to form a third resistor bridge network;
• and
• arranging a conductor in proximity to the third magnetic sensor unit,
• wherein passing a current through the conductor aligns a magnetization vector of the third magnetic sensor unit,
• wherein forming the first, second, and third magnetic sensor units comprises arranging the first, second, and third magnetic sensor units respectively so that the first, second, and third magnetic sensor units sense magnetic field components in mutually orthogonal directions,
• wherein the first, second, and third sets of conductive straps are arranged to form angles of approximately 45 degrees with respect to the first, second, and third sets of magnetoresistive strips respectively, and
• wherein the first, second, and third sets of conductive straps provide a linear operating range for the first, second, and third sets of magnetoresistive strips.

A method of fabricating an integrated three-dimensional magnetic sensing device, the method comprising:

• forming on a single substrate a first sloped surface and a second sloped surface, wherein the first sloped surface is opposite the second sloped surface, and wherein an angle of the first sloped surface is substantially equal to an angle of the second sloped surface;
• forming a first magnetic sensor unit on a first surface area of the single substrate;
• forming a second magnetic sensor unit on a second surface area of the single substrate;
• forming a third magnetic sensor unit on the first and second sloped surfaces of the single substrate, wherein the first and second sloped surfaces are sloped with respect to the first and second surface areas, and
• arranging a biasing means on the third magnetic sensor unit,
• whereby the biasing means provides a cancelling effect on horizontal components of a magnetic field such that the third magnetic sensor unit is sensitive to only vertical components of the magnetic field.

A method of fabricating an integrated three-dimensional magnetic sensing device, the method comprising:

• forming a first magnetic sensor unit on a first surface area of a single substrate;
• forming a second magnetic sensor unit on a second surface area of the single substrate;
• and
• forming a third magnetic sensor unit on at least one sloped surface of the single substrate, wherein the at least one sloped surface is sloped with respect to the first and second surface areas,
• wherein forming the first, second, and third magnetic sensor units comprises arranging the first, second, and third magnetic sensor units respectively so that the first, second, and third magnetic sensor units sense magnetic field components in mutually orthogonal directions,
• wherein the at least one sloped surface of the single substrate comprises a first sloped surface and a second sloped surface,
• wherein the first sloped surface is opposite the second sloped surface,
• wherein an angle of the first sloped surface is substantially equal to an angle of the second sloped surface, and
• wherein the third magnetic sensor unit includes a biasing means that provides a cancelling effect on horizontal components of a magnetic field such that the third magnetic sensor unit is sensitive to only vertical components of the magnetic field.