Magnetic tunnel junction device with improved barrier layer

A method for forming an array of magnetic tunnel junction (MTJ) devices, comprising:

• providing a first ferro-magnetic electrode;
• depositing a first layer of a first oxidizable material of a first thickness on the first electrode;
• exposing the first layer of first oxidizable material to a first natural oxidation process at a predetermined first pressure for a predetermined first time, to convert a portion of the first layer of first oxidizable material to a first insulating oxide;
• depositing a second layer of a second oxidizable material of a second thickness on the first insulating oxide;
• exposing the second layer of second oxidizable material to a further rapid oxidation process providing substantially accelerated oxidation compared to the first natural oxidation process, so as to convert at least the second layer of second oxidizable material to a further insulating oxide contiguous with the first insulating oxide;
• and
• providing a second ferro-magnetic electrode on the further insulating oxide.

A method for forming a metal-insulating-metal tunneling structure of a magnetic tunnel junction device, comprising:

• providing a first ferro-magnetic electrode;
• depositing a first layer of a first oxidizable material of a first thickness on the first electrode;
• first exposing the first layer of the first oxidizable material to a natural oxidation process to convert a part of the first layer of first oxidizable material to a first insulating oxide portion;
• second exposing the first insulating oxide portion to a further rapid oxidation process providing substantially accelerated oxidation compared to the natural oxidation process, so as to convert some or all of the remaining oxidizable material to a second insulating oxide portion contiguous with the first insulating oxide portion whereby the combination of the first and second insulating oxide portions forms an insulating layer on the first ferro-magnetic electrode;
• and
• providing a second ferro-magnetic electrode on the insulating layer to form the metal-insulator-metal tunneling structure of the magnetic tunnel junction device.