Magnetic Sensor Array with Dual TMR Film

A TMR sensor device, comprising:

• a first resistor comprising a first TMR film, the first TMR film comprising a first reference layer having a first magnetization direction, wherein the first reference layer comprises a CoFe/Ta/CoFeB/CoFe multilayer stack having a thickness between about 21 Angstroms and about 37 Angstroms;
• a second resistor comprising a second TMR film, the second TMR film comprising a second reference layer having a second magnetization direction, wherein the second reference layer comprises a CoFe/Ta/CoFeB/CoFe multilayer stack having a thickness between about 21 Angstroms and about 37 Angstroms, and wherein the first magnetization direction of the first reference layer of the first TMR film is anti-parallel to the second magnetization of the second reference layer of the second TMR film;
• a third resistor comprising the second TMR film;
• and
• a fourth resistor comprising the first TMR film.

A method of fabricating a TMR sensor device having a first resistor, a second resistor, a third resistor, and a fourth resistor, comprising:

• forming a first TMR film by:
• depositing a first seed layer,
• depositing a first antiferromagnetic layer on the first seed layer,
• depositing a first pinned layer on the first antiferromagnetic layer, the first pinned layer comprising a Co/CoFe/Co multi-layer stack having a thickness between about 20 Angstroms and about 30 Angstroms,
• depositing a first spacer layer on the first pinned layer,
• depositing a first reference layer on the first spacer layer, the first reference layer comprising a CoFe/Ta/CoFeB/CoFe multilayer stack having a thickness between about 21 Angstroms and about 37 Angstroms,
• depositing a first barrier layer on the first reference layer, and
• depositing a first free layer on the first barrier layer;
• magnetically annealing the first TMR film to change a first magnetization direction of the first reference layer to be anti-parallel to a second magnetization direction of the first pinned layer;
• forming a second TMR film by:
• depositing a second seed layer,
• depositing a second antiferromagnetic layer on the second seed layer,
• depositing a second pinned layer on the second antiferromagnetic layer, the second pinned layer comprising a Co/CoFe/Co multi-layer stack having a thickness between about 20 Angstroms and about 30 Angstroms,
• depositing a second spacer layer on the second pinned layer,
• depositing a third pinned layer on the second spacer layer, the third pinned layer comprising a Co/CoFe/Co multi-layer stack having a thickness between about 35 Angstroms and about 55 Angstroms,
• depositing a third spacer layer on the third pinned layer,
• depositing a second reference layer on the third spacer layer, the second reference layer comprising a CoFe/Ta/CoFeB/CoFe multilayer stack having a thickness between about 21 Angstroms and about 37 Angstroms,
• depositing a second barrier layer on the second reference layer, and
• depositing a second free layer on the second barrier layer;
• magnetically annealing the second TMR film to change a third magnetization direction of the third pinned layer to be anti-parallel to a fourth magnetization direction of the second reference layer, wherein the first magnetization direction of the first reference layer of the first TMR film is anti-parallel to the fourth magnetization direction of the second reference layer of the second TMR film;
• forming the first resistor and the fourth resistor from the first TMR film;
• and
• forming the second resistor and the third resistor from the second TMR film, wherein the first resistor is adjacent to the second resistor and the third resistor, the second resistor is adjacent to the first resistor and the fourth resistor, the third resistor is adjacent to the first resistor and the fourth resistor, and the fourth resistor is adjacent to the second resistor and the third resistor.