Magnetic tunnel junction (mtj) element and its fabrication process
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsTSANN LIN, YA-LING LEE
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Abstract
A magnetic tunnel junction (MTJ) element is provided. The MTJ element includes a buffer layer, a seed layer disposed over the buffer layer, a first ferromagnetic layer disposed over the seed layer, a tunnel barrier layer disposed over the first ferromagnetic layer and a second ferromagnetic layer disposed over the tunnel barrier layer. The seed layer includes a Cobalt (Co)-based film. The buffer layer includes cobalt (Co) and hafnium (Hf). The buffer layer is alloyed with chromium and has chromium content up to 20 at. %. The MTJ element in accordance with the present disclosure exhibits a low resistance desired for a low-power write operation, and a high TMR coefficient desired for a low bit-error-rate (BER) read operation.
Claims20
A semiconductor device, comprising:
- a buffer layer;
- a seed layer disposed over the buffer layer;
- a first ferromagnetic layer disposed over the seed layer;
- a tunnel barrier layer disposed over the first ferromagnetic layer;
- and
- a second ferromagnetic layer disposed over the tunnel barrier layer,
- wherein the buffer layer, the seed layer, the first ferromagnetic layer and the second ferromagnetic layer contain cobalt (Co),
- wherein the seed layer and the buffer layer comprise a cobalt (Co)-based film;
- wherein the buffer layer further comprises hafnium (Hf);
- and
- wherein the buffer layer is doped with nitrogen and has nitrogen content up to 30 at. %.
A semiconductor device, comprising:
- a bottom electrode;
- a buffer layer disposed over the bottom electrode;
- a seed layer disposed over the buffer layer;
- at least one ferromagnetic layer disposed over the seed layer;
- a top electrode disposed over the at least one ferromagnetic layer,
- wherein the buffer layer, the seed layer and the at least one ferromagnetic layer contain cobalt (Co),
- wherein the buffer layer further comprises hafnium (Hf);
- and
- wherein the buffer layer is doped with nitrogen and has nitrogen content up to 30 at. %.
A method for manufacturing a semiconductor device, comprising:
- forming a buffer layer over a bottom electrode layer;
- doping the buffer layer with nitrogen so that the buffer layer has a nitrogen content up to 30 at. %;
- forming a seed layer over the buffer layer;
- forming a hard-bias layer over the seed layer;
- and
- forming an MTJ stack comprising a first ferromagnetic layer, a tunnel barrier layer and a second ferromagnetic layer over the hard-bias layer,
- wherein the seed layer and the buffer layer comprise a cobalt (Co)-based film, and
- wherein the buffer layer further comprises hafnium (Hf).
Dependencies are inferred from the claim text.