Magnetic detection element
View Patent ↗Embodiments of the present invention help to reduce etching damage at end parts of a magnetoresistive sensor in ion beam etching. According to one embodiment, ion beam etching (IBE) is used in a magnetoresistive sensor track width forming step. This IBE irradiates Ar ion beam to a substrate in a state that the substrate is inclined and further rotates the substrate about its normal as a rotational axis. In a conventional track width forming step, the IBE irradiates the Ar ion beam to the substrate all the time while the IBE is rotating the substrate. By contrast, the IBE according to embodiments of the present invention irradiates the Ar ion beam to the substrate only in a predetermined specific angular range.
1. A magnetic detection element including a magnetoresistive sensor multilayer film having a fixed layer whose magnetization direction is fixed, a free layer whose magnetization direction is changed in accordance with an external magnetic field, and a non-magnetic intermediate layer between the fixed layer and the free layer; current flowing in a perpendicular direction to a plane of the magnetoresistive sensor multilayer film; and the magnetic detection element comprising:
an upper shield electrode and a lower shield electrode formed so as to sandwich the magnetoresistive sensor multilayer film in the top-bottom direction;
magnetic domain control films formed at both sides of the magnetoresistive sensor multilayer film for applying bias fields to the free layer;
a sensor multilayer film lower layer formed lower than the fixed layer, the free layer, and the non-magnetic intermediate layer, and having level differences, thicknesses thereof becoming smaller as getting away from the magnetoresistive sensor multilayer film; and
insulating films formed in contact with the both side ends of the magnetoresistive sensor multilayer film having level differences such that thicknesses of the insulating films are formed thinner on the magnetoresistive sensor multilayer film side in accordance with the level differences of the sensor multilayer film lower layer,
wherein the magnetic domain control films have about-horizontally-oriented portions of both upper and lower surfaces thereof positioned vertically above the sensor multilayer film lower layer.
2. The magnetic detection element according to claim 1 , wherein angles of end parts of the fixed layer, the free layer, and the non-magnetic intermediate layer are not less than 45°.
3. The magnetic detection element according to claim 1 , wherein the upper shield electrode is substantially flat in a region overlapping the magnetoresistive sensor multilayer film; and
a width of the substantially flat region at a media-facing side of the magnetic detection element is not less than a sum of a track width of the free layer at the media-facing side and a value twice as large as a space between the upper shield electrode and the lower shield electrode.
4. The magnetic detection element according to claim 1 , wherein the fixed layer, the non-magnetic intermediate layer, and the free layer are sequentially stacked and arranged in order from the lower side to the upper side;
the magnetic domain control film has a level difference such that thickness thereof is formed thinner at the magnetoresistive sensor multilayer film side; and
the level position of the top surface of the magnetic domain control film in a vicinity of a side end of the magnetoresistive sensor multilayer film is lower than the top surface position of the magnetoresistive sensor multilayer film by not more than 5 nm.
5. A magnetic detection element according to claim 1 , wherein the magnetic domain control film has a level difference such that thickness thereof is formed thinner at the magnetoresistive sensor multilayer film side; and
in the level difference of the magnetic domain control film, the thickness of the magnetic domain control film at the magnetoresistive sensor multilayer film side between the about-horizontally-oriented portions of both the upper and lower surfaces of the magnetic domain control film positioned vertically above the sensor multilayer film lower layer is one-half of the thickness of the magnetic domain control film in a portion thereof not positioned vertically above the sensor multilayer film lower layer.
6. The magnetic detection element according to claim 1 , wherein an uppermost surface of the sensor multilayer film has a first portion under the fixed layer at a first vertical level, wherein the uppermost surface of the sensor multilayer film has a second portion not under the fixed layer and positioned at a second level lower than the first level, wherein the second portion of the uppermost surface is oriented about parallel to the first portion.
7. A magnetic detection element including a magnetoresistive sensor multilayer film having a fixed layer whose magnetization direction is fixed, a free layer whose magnetization direction is changed in accordance with an external magnetic field, and a non-magnetic intermediate layer between the fixed layer and the free layer; current flowing in a perpendicular direction to a plane of the magnetoresistive sensor multilayer film; and the magnetic detection element comprising:
an upper shield electrode and a lower shield electrode formed so as to sandwich the magnetoresistive sensor multilayer film in the top-bottom direction;
magnetic domain control films formed at both sides of the magnetoresistive sensor multilayer film for applying bias fields to the free layer;
a sensor multilayer film lower layer formed lower than the fixed layer, the free layer, and the non-magnetic intermediate layer, and having level differences, thicknesses thereof becoming smaller as getting away from the magnetoresistive sensor multilayer film, wherein an uppermost surface of the sensor multilayer film has a first portion under the fixed layer at a first vertical level, wherein the uppermost surface of the sensor multilayer film has a second portion not under the fixed layer and positioned at a second level lower than the first level, wherein the second portion of the uppermost surface is oriented about parallel to the first portion; and
insulating films formed in contact with the both side ends of the magnetoresistive sensor multilayer film having level differences such that thicknesses of the insulating films are formed thinner on the magnetoresistive sensor multilayer film side in accordance with the level differences of the sensor multilayer film lower layer.
8. The magnetic detection element according to claim 7 , wherein angles of end parts of the fixed layer, the free layer, and the non-magnetic intermediate layer are not less than 45°.
9. The magnetic detection element according to claim 7 , wherein the upper shield electrode is substantially flat in a region overlapping the magnetoresistive sensor multilayer film; and
a width of the substantially flat region at a media-facing side of the magnetic detection element is not less than a sum of a track width of the free layer at the media-facing side and a value twice as large as a space between the upper shield electrode and the lower shield electrode.
10. The magnetic detection element according to claim 7 , wherein the fixed layer, the non-magnetic intermediate layer, and the free layer are sequentially stacked and arranged in order from the lower side to the upper side;
the magnetic domain control film has a level difference such that thickness thereof is formed thinner at the magnetoresistive sensor multilayer film side; and
the level position of the top surface of the magnetic domain control film in a vicinity of a side end of the magnetoresistive sensor multilayer film is lower than the top surface position of the magnetoresistive sensor multilayer film by not more than 5 nm.
11. A magnetic detection element according to claim 7 , wherein the magnetic domain control film has a level difference such that thickness thereof is formed thinner at the magnetoresistive sensor multilayer film side; and
in the level difference of the magnetic domain control film, the thickness at the magnetoresistive sensor multilayer film side is one-half of the thickness of an opposite side of the magnetoresistive sensor multilayer film side.