Structure of tmr and fabrication method of integrated 3-axis magnetic field sensor and sensing circuit

An in-plane magnetic field sensor, comprising:

• a substrate;
• and
• a magnetic sensing structure of tunneling magneto-resistor (TMR) on the substrate,
• wherein the magnetic sensing structure of TMR comprises:
• a bottom electrode;
• a first magnetic tunneling junction (MTJ) device, comprising:
• a first pinned layer on the bottom electrode, having a first pinned magnetization at a pinned direction;
• a first tunneling layer, disposed on the first pinned layer;
• and
• a first magnetic free layer, disposed on the first tunneling layer, having a first free magnetization parallel to an easy axis and an included angle formed between the pinned direction and the easy axis;
• a second MTJ device with an identical structure to the first MTJ device, comprising:
• a second pinned layer on the bottom electrode, having a second pinned magnetization at the pinned direction;
• a second tunneling layer, disposed on the second pinned layer;
• and
• a second magnetic free layer, disposed on the second tunneling layer, having a second free magnetization parallel to the easy axis;
• a top electrode, connecting the first free layer and the second free layer;
• and
• wherein the included angle between the pinned direction and the easy axis is substantially 45 or 135 degrees,
• wherein a magnetic field sensing direction is perpendicular to the easy axis on the substrate.

A 2-axis in-plane magnetic field sensor, comprising:

• a substrate and
• a first in-plane magnetic field sensor on the substrate, having a first pinned direction and a first easy axis;
• and
• a second in-plane magnetic field sensor on the substrate, having a second pinned direction and a second easy axis, wherein the first easy axis is orthogonal to the second easy axis, and the first pinned direction and the second pinned direction both are parallel to a bisection direction, the bisection direction having an angle of 45 degrees to the first easy axis and the second easy axis, respectively,
• wherein the first in-plane magnetic field sensor comprises:
• a first magnetic sensing structure of TMR comprising:
• a first bottom electrode on the substrate;
• a first magnetic tunneling junction (MTJ) device, comprising:
• a first pinned layer on the first bottom electrode, having a first pinned magnetization at the first pinned direction;
• a first tunneling layer, disposed on the first pinned layer;
• and
• a first magnetic free layer, disposed on the first tunneling layer, having a first free magnetization parallel to the first easy axis and a first included angle formed between the first pinned direction and the first easy axis;
• a second MTJ device, comprising:
• a second pinned layer on the first bottom electrode, having a second pinned magnetization at the first pinned direction;
• a second tunneling layer, disposed on the second pinned layer;
• and
• a second magnetic free layer, disposed on the second tunneling layer, having a second free magnetization parallel to the first easy axis;
• and
• a first top electrode, connecting the first free layer and the second free layer,
• wherein the first free magnetization and the second free magnetization at an initial state are parallel to the first easy axis but mutual anti-parallel, and the first included angle between the first pinned direction and the first easy axis is substantially 45 or 135 degrees, wherein a first magnetic field sensing direction is perpendicular to the first easy axis on the substrate,
• wherein the second in-plane magnetic field sensor comprises:
• a second magnetic sensing structure of TMR comprising:
• a second bottom electrode on the substrate;
• a third MTJ device, comprising:
• a third pinned layer on the second bottom electrode, having a third pinned magnetization at the second pinned direction;
• a third tunneling layer, disposed on the third pinned layer;
• and
• a third magnetic free layer, disposed on the third tunneling layer, having a third free magnetization parallel to the second easy axis and a second included angle formed between the second pinned direction and the second easy axis;
• a fourth MTJ device, comprising:
• a fourth pinned layer on the second bottom electrode, having a fourth pinned magnetization at the second pinned direction;
• a fourth tunneling layer, disposed on the fourth pinned layer;
• and
• a fourth magnetic free layer, disposed on the fourth tunneling layer, having a fourth free magnetization parallel to the second easy axis;
• and
• a second top electrode, connecting the third magnetic free layer and the fourth magnetic free layer;
• wherein the third free magnetization and the fourth free magnetization at the initial state are parallel to the second easy axis but mutual anti-parallel, and the second included angle between the second pinned direction and the second easy axis is substantially 45 or 135 degrees, wherein a second magnetic field sensing direction is perpendicular to the second easy axis on the substrate.

An out-of-plane magnetic field sensor over a substrate having a magnetic field sensing direction perpendicular to the substrate, comprising:

• a groove or bulge structure on the substrate, having a first incline and a second incline, wherein the first incline and the second incline have a same bevel to the substrate and are symmetrically flipped with respect to a medial axle of the groove or bulge structure;
• a first magnetic field sensing structure of tunneling magneto-resistor (TMR) formed on the first incline, having a first pinned direction and a first easy axis, comprising:
• a first bottom electrode on the first incline;
• a first magnetic tunneling junction (MTJ) device, comprising:
• a first pinned layer on the first bottom electrode, having a first pinned magnetization at the first pinned direction;
• a first tunneling layer, disposed on the first pinned layer;
• and
• a first magnetic free layer, disposed on the first tunneling layer, having a first free magnetization parallel to the first easy axis and a first included angle formed between the first pinned direction and the first easy axis;
• a second MTJ device, comprising:
• a second pinned layer on the first bottom electrode, having a second pinned magnetization at the first pinned direction;
• a second tunneling layer, disposed on the second pinned layer;
• and
• a second magnetic free layer, disposed on the second tunneling layer, having a second free magnetization parallel to the first easy axis;
• and
• a first top electrode, connecting the first magnetic free layer and the second magnetic free layer, wherein the first free magnetization and the second free magnetization at an initial state are parallel to the first easy axis but mutual anti-parallel;
• and
• a second magnetic field sensing structure of TMR formed on the second incline, having a second pinned direction and a second easy axis, comprising:
• a second bottom electrode on the first incline;
• a third MTJ device, comprising:
• a third pinned layer on the second bottom electrode, having a third pinned magnetization at the second pinned direction;
• a third tunneling layer, disposed on the third pinned layer;
• and
• a third magnetic free layer, disposed on the third tunneling layer, having a third free magnetization parallel to the second easy axis and a second included angle formed between the second pinned direction and the second easy axis;
• a fourth MTJ device, comprising:
• a fourth pinned layer on the second bottom electrode, having a fourth pinned magnetization at the second pinned direction;
• a fourth tunneling layer, disposed on the fourth pinned layer;
• and
• a fourth magnetic free layer, disposed on the fourth tunneling layer, having a fourth free magnetization parallel to the second easy axis;
• and
• a second top electrode, connecting the third magnetic free layer and the fourth magnetic free layer, wherein the third free magnetization and the fourth free magnetization at the initial state are parallel to the second easy axis but mutual anti-parallel,
• wherein the first easy axis and the second easy axis are parallel to the medial axle of the groove or bulge structure, the first bottom electrode of the first magnetic field sensing structure of TMR connects with the second bottom electrode of the second magnetic field sensing structure of TMR, and the first top electrode of the first magnetic field sensing structure of TMR connects with the second top electrode of the second magnetic field sensing structure of TMR.

A 3-axis magnetic field sensor, comprising:

• a first in-plane magnetic field sensor on a substrate to sense an X magnetic field, having a first magnetic field sensing structure of TMR and having a first pinned direction and a first easy axis, wherein the first easy axis is regarded as a Y-axis;
• and
• a second in-plane magnetic field sensor on the substrate to sense a Y magnetic field, having a second magnetic field sensing structure of TMR and having a second pinned direction and a second easy axis, wherein the second easy axis is regarded as an X-axis,
• wherein the first easy axis and the second easy axis are orthogonal, and a bisection direction on the substrate has an angle of 45 degrees to the first easy axis and the second easy axis, respectively,
• an out-of-plane magnetic field sensor on the substrate to sense a Z magnetic field, having a medial axle is parallel to the bisection direction.