Method of fabricating memory device including magnetic tunnel junctions with insulating sidewalls
A method of manufacturing a memory device includes sequentially forming a first magnetization layer, a tunnel barrier layer, and a second magnetization layer on each other; forming a magnetic tunnel junction structure by patterning the first magnetization layer, the tunnel barrier layer, and the second magnetization layer; forming a sidewall metal layer by etching a portion of a redeposited metal covering a sidewall of the magnetic tunnel junction structure; performing an oxidizing operation that includes oxidizing an exposed surface of the sidewall metal layer to provide an oxidized sidewall metal layer; and performing an irradiating operation that includes irradiating an ion beam towards the oxidized sidewall metal layer. A sidewall insulating layer covering a sidewall of the magnetic tunnel junction structure is formed by alternately performing the oxidizing operation and the irradiating operation two or more times.
1 . A method of manufacturing a memory device, the method comprising:
sequentially forming a first magnetization layer, a tunnel barrier layer, and a second magnetization layer on each other;
forming a magnetic tunnel junction structure by patterning the first magnetization layer, the tunnel barrier layer, and the second magnetization layer, the forming the magnetic tunnel junction structure including forming a redeposited metal covering a sidewall of the magnetic tunnel junction structure;
forming a sidewall metal layer by etching a portion of the redeposited metal;
performing an oxidizing operation that includes oxidizing an exposed surface of the sidewall metal layer to provide an oxidized portion of the sidewall metal layer; and
performing an irradiating operation that includes irradiating an ion beam toward the oxidized portion of the sidewall metal layer,
wherein a sidewall insulating layer covers a sidewall of the magnetic tunnel junction structure and is formed by alternately performing the oxidizing operation and the irradiating operation two or more times.
2 . The method of claim 1 , wherein
in performing the oxidizing operation, as a surface energy of the sidewall metal layer increases according to irradiation of the ion beam in the irradiating operation, a metal on the exposed surface of the sidewall metal layer bonds with oxygen atoms.
3 . The method of claim 2 , wherein the metal on the exposed surface of the sidewall metal layer bonds with the oxygen atoms according to a natural oxidation process.
4 . The method of claim 1 , wherein,
in the performing the irradiating operation, the ion beam removes a portion of a metal and a portion of a metal oxide from a surface of the oxidized portion of the sidewall metal layer.
5 . The method of claim 4 , wherein a portion of the removed portion of the metal oxide is re-attached to the sidewall metal layer.
6 . The method of claim 1 , wherein
the sidewall insulating layer comprises a metal oxide,
a metal constituting the metal oxide and a metal constituting the sidewall metal layer are substantially a same metal.
7 . The method of claim 1 , wherein,
in the performing the oxidizing operation, a surface of the sidewall metal layer is changed from an unstable state to a stable state,
wherein, in the performing the irradiating operation, the surface of the sidewall metal layer is changed from the stable state to the unstable state.
8 . The method of claim 1 , wherein
in the performing the irradiating operation, the irradiating the ion beam is performed during an ion beam etching process, and
the ion beam comprises inert gas ions.
9 . The method of claim 1 , wherein,
in the forming the sidewall metal layer, a remaining unetched portion of the redeposited metal constitutes the sidewall metal layer.
10 . The method of claim 1 , wherein the performing the oxidizing operation and the performing the irradiating operation are performed in one process chamber.
11 . A method of manufacturing a memory device, the method comprising:
sequentially forming a first magnetization layer, a tunnel barrier layer, and a second magnetization layer on each other;
forming a magnetic tunnel junction structure by patterning the first magnetization layer, the tunnel barrier layer, and the second magnetization layer, the forming the magnetic tunnel junction structure including forming a redeposited metal covering a sidewall of the magnetic tunnel junction structure;
forming a sidewall metal layer by etching a portion of a redeposited metal;
performing an oxidizing operation that includes oxidizing an exposed surface of the sidewall metal layer by irradiating an ion beam of oxygen ions toward the exposed surface of the sidewall metal layer to provide an oxidized portion of the sidewall metal layer; and
etching the oxidized portion of the sidewall metal layer by irradiating an ion beam of inert gas ions toward the oxidized portion of the sidewall metal layer, and
the performing the oxidizing operation and the performing etching operation being performed in one chamber at a same time to form a sidewall insulating layer covering the sidewall of the magnetic tunnel junction structure.
12 . The method of claim 11 , wherein,
in performing the oxidizing operation, as a surface energy increases according to irradiation of the ion beam of oxygen ions, a metal is combined with the oxygen ions on the exposed surface of the sidewall metal layer.
13 . The method of claim 11 , wherein
the ion beam of oxygen ions oxidizes a portion of the redeposited metal at the exposed surface of the sidewall metal layer, and
the ion beam of inert gas ions removes a portion of the metal and a portion of metal oxide from the surface of the oxidized portion of the sidewall metal layer.
14 . The method of claim 13 , wherein a portion of the removed portion of the metal oxide, removed by the ion beam of the inert gas ions, is re-attached to the sidewall metal layer.
15 . The method of claim 11 , wherein,
in the forming the magnetic tunnel junction structure, the redeposited metal is an etching by-product in which a portion of the first magnetization layer and a portion of the second magnetization layer are etched and reattached to the sidewall of the magnetic tunnel junction structure.
16 . A method of manufacturing a memory device, the method comprising:
sequentially forming a first magnetization layer, a tunnel barrier layer, and a second magnetization layer on each other;
forming a magnetic tunnel junction structure by patterning the first magnetization layer, the tunnel barrier layer, and the second magnetization layer, the forming the magnetic tunnel junction structure including forming a redeposited metal covering a sidewall of the magnetic tunnel junction structure;
forming a sidewall metal layer by etching a portion of the redeposited metal; and
forming a sidewall insulating layer covering the sidewall of the magnetic tunnel junction structure by oxidizing the sidewall metal layer,
the forming the sidewall insulating layer including alternately performing a process of oxidizing of an exposed surface of the sidewall metal layer to provide an oxidized sidewall of the metal layer and a process of irradiating the oxidized sidewall of the metal layer with a first ion beam of inert gas ions, and
the forming the sidewall insulating layer, after the alternately performing the process of oxidizing and the process of irradiating is performed two or more times, further including an operation of irradiating the exposed surface of the sidewall metal layer with a second ion beam including reactive ions and inert gas ions.
17 . The method of claim 16 , wherein,
in the process of oxidizing during the forming the sidewall insulating layer, a surface of the sidewall metal layer changes from an unstable state to a stable state, and
in the process of irradiating the oxidized sidewall of the metal layer with the first ion beam during the forming the sidewall insulating layer, the surface of the sidewall metal layer changes from the stable state to the unstable state.
18 . The method of claim 16 , wherein
in the forming the sidewall insulating layer, the process of irradiating the oxidized sidewall of the metal layer with the first ion beam is an etching process using the inert gas ions.
19 . The method of claim 16 , wherein
in the forming the sidewall insulating layer, the irradiating the exposed surface of the sidewall metal layer with the second ion beam comprises an oxidation process using the reactive ions and an etching process using the inert gas ions.
20 . The method of claim 16 , wherein in the forming the sidewall insulating layer, the process of irradiating the oxidized sidewall of the metal layer with the first ion beam and the operation of irradiating the exposed sidewall of the metal layer with the second ion beam are performed in one process chamber.