Method of manufacturing magnetoresistance element using laser pinning process
In one aspect, a method of manufacturing a magnetoresistance (MR) element having layers include ramping up a temperature of a reference layer of the MR element to an annealing temperature of the reference layer by increasing an amplitude of laser pulses applied to the reference layer over time to an amplitude that corresponds to the annealing temperature of the reference layer; applying a magnetic field to the reference layer; and maintaining the amplitude of subsequent laser pulses over time that have the amplitude that corresponds to the annealing temperature of the reference layer until at least the reference layer is annealed.
1 . A method of manufacturing a magnetoresistance (MR) element having layers, comprising:
raising a temperature of an insulator layer of the MR element to a crystallization temperature of the insulator layer by increasing an amplitude of laser pulses applied to the insulator layer over time to an amplitude that corresponds to the crystallization temperature of the insulator layer;
maintaining the amplitude of subsequent laser pulses over time that have the amplitude that corresponds to the crystallization temperature of the insulator layer until at least the insulator layer is crystallized;
after maintaining the amplitude of subsequent laser pulses over time that have the amplitude that corresponds to the crystallization temperature of the insulator layer, lowering the temperature of the insulator layer by reducing amplitudes of subsequent laser pulses applied to the insulator layer to a temperature that corresponds to an annealing temperature of a reference layer of the MR element;
applying the laser pulses that correspond to the annealing temperature of the reference layer of the MR element to the reference layer;
maintaining the amplitude of subsequent laser pulses over time that have the amplitude that corresponds to the annealing temperature of the reference layer until at least the reference layer is annealed; and
after maintaining the amplitude of subsequent laser pulses over time that have the amplitude that corresponds to the annealing temperature of the reference layer, ramping down the temperature of the reference layer by decreasing an amplitude of subsequent laser pulses applied to the reference layer over time.
2 . The method of claim 1 , wherein the reference layer comprises cobalt, iron and/or boron.
3 . The method of claim 1 , wherein the insulator layer is magnesium oxide.
4 . The method of claim 1 , wherein the MR element is a giant magnetoresistance element (GMR) or a tunneling magnetoresistance element (TMR).
5 . The method of claim 1 , wherein ramping down the temperature of the reference layer by decreasing an amplitude of subsequent laser pulses applied to the reference layer over time comprises decreasing amplitudes of subsequent laser pulses at a rate of reduction that is slower than a rate of reduction of amplitudes of laser pulses that would cause interstitial damage between the layers of the MR.