| US 7,352,021 B2 | ||
| Magnetic random access memory devices having titanium-rich lower electrodes with oxide layer and oriented tunneling barrier | ||
| Jun-Soo Bae, Gyeonggi-do (Korea, Republic of); Jang-Eun Lee, Gyeonggi-do (Korea, Republic of); Hyun-Jo Kim, Gyeonggi-do (Korea, Republic of); In-Gyu Baek, Seoul (Korea, Republic of); and Young-Ki Ha, Gyeonggi-do (Korea, Republic of) | ||
| Assigned to Samsung Electronics Co., Ltd., (Korea, Republic of) | ||
| Filed on Jul. 09, 2004, as Appl. No. 10/888,964. | ||
| Claims priority of application No. 10-2003-0046796 (KR), filed on Jul. 10, 2006. | ||
| Prior Publication US 2005/0006682 A1, Jan. 13, 2005 | ||
| Int. Cl. H01L 29/76 (2006.01) | ||
| U.S. Cl. 257—295 [438/3; 438/238; 257/E43.004; 257/E43.006] | 14 Claims |
| 1. A magnetic tunnel junction structure for a magnetic random access memory comprising:
a lower electrode that comprises a Ti-rich TiN layer having a titanium (Ti) content of between about 70 and about 90 atomic
percent, the Ti-rich TiN layer having a lower chemical mechanical polishing rate than a stoichiometric TiN layer and having
a surface roughness that is also lower than a stoichiometric TiN layer;
an oxide layer on the lower electrode; and
a magnetic tunnel junction on the oxide layer, the magnetic tunnel junction comprising:
a fixed layer including a seed layer;
a tunneling barrier on the seed layer, that is oriented in a same crystalline direction as a most closely packed plane direction
of the seed layer, the surface roughness of the tunneling barrier being reduced by the lower surface roughness of the Ti-rich
TiN layer; and
a free layer on the tunneling barrier.
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