Method for fabricating magnetoresistive random access memory element

A method for fabricating a magnetoresistive random access memory (MRAM) element, comprising:

• providing a substrate;
• depositing a first insulating layer on the substrate;
• forming a first bottom electrode and a second bottom electrode in the first insulating layer, wherein the first bottom electrode is spaced apart from the second bottom electrode;
• depositing a second insulating layer on the first insulating layer and on the first and second bottom electrodes;
• forming a first via hole in the second insulating layer, wherein the first via hole exposes a top surface of the first and second bottom electrodes and a portion of the insulating layer between the first and second bottom electrodes;
• forming a first reference layer on a first sidewall in the first via hole and a second reference layer on a second sidewall in the first via hole;
• forming a patterned sacrificial layer on the first insulating layer and on the first and second reference layers;
• laterally etching the first and second reference layers from a side not masked by the patterned sacrificial layer, thereby turning the first and second reference layers into a first reference pillar and a second reference pillar respectively;
• removing the patterned sacrificial layer;
• filling the first via hole with a first gap fill material layer;
• depositing a barrier layer on the second insulating layer, the reference layer and the first gap fill material layer;
• depositing a third insulating layer on the barrier layer;
• forming a second via hole in the third insulating layer;
• forming a first free layer and a second free layer in the second via hole, wherein the first free layer is situated directly above the first reference pillar and the second free layer is situated directly above the second reference pillar;
• filling the second via hole with a second gap fill material layer;
• and
• forming a first and second top electrodes on the first and second free layers respectively.