Method for manufacturing semiconductor structure with memory device

A method for manufacturing a semiconductor structure, comprising:

• forming a pinned layer over a substrate;
• forming a tunnel barrier layer over the pinned layer;
• forming a free layer over the tunnel barrier layer, wherein the free layer is made of a first material;
• and
• etching the free layer, the tunnel barrier layer, and the pinned layer to form a magnetic tunnel junction (MTJ) stack structure comprising a free layer structure, a tunnel barrier layer structure, and a pinned layer structure by performing a first ion beam etching process,
• wherein the first ion beam etching process comprises using a first etching gas, and the first etching gas is formed of a first compound having a first molecular mass, wherein a difference between the first molecular mass of the first compound and a molecular mass of the first material is lower than 40, and
• wherein the tunnel barrier layer structure is wider than a top surface of the pinned layer structure.

A method for manufacturing a semiconductor structure, comprising:

• sequentially forming a bottom electrode layer, a pinned layer, a tunnel barrier layer, and a free layer over a substrate;
• patterning the free layer to form a free layer structure having a first sloped sidewall;
• etching the tunnel barrier layer to form a tunnel barrier layer structure below the free layer structure;
• etching the pinned layer to form a pinned layer structure having a second sloped sidewall below the tunnel barrier layer structure;
• etching the bottom electrode layer to form a bottom electrode structure having a third sloped sidewall below the pinned layer structure;
• and
• forming a spacer over the first sloped sidewall of the free layer structure, the second sloped sidewall of the pinned layer structure, and the third sloped sidewall of the bottom electrode structure,
• wherein a protruding portion of the tunnel barrier layer structure laterally protrudes from the first sloped sidewall and the second sloped sidewall and extending into the spacer, and the spacer is in contact with both a top surface and a bottom surface of the protruding portion of the tunnel barrier layer.