An object is to provide a semiconductor device of which a manufacturing process is not complicated and by which cost can be suppressed, by forming a thin film transistor using an oxide semiconductor film typified by zinc oxide, and a manufacturing method thereof. For the semiconductor device, a gate electrode is formed over a substrate; a gate insulating film is formed covering the gate electrode; an oxide semiconductor film is formed over the gate insulating film; and a first conductive film and a second conductive film are formed over the oxide semiconductor film. The oxide semiconductor film has at least a crystallized region in a channel region.

Semiconductor device, and manufacturing method thereof

Perpendicular recording technology has recently been introduced in hard disk drives for computer and consumer electronics applications. Although conceptualized in the late 1970s, making a product with perpendicular recording that has competing performance, reliability, and price advantage over the prevalent longitudinal recording technology has taken about three decades. One reason for the late entry of perpendicular recording is that the longitudinal recording technology was quite successful in overcoming many of its problems and in staying competitive. Other reasons are the risks, problems, and investment needed in making a successful transition to perpendicular recording technology. Iwasaki and co-workers came up with many inventions in the late 1970s, such as single-pole head, CoCr alloy media with a perpendicular anisotropy, and recording media with soft magnetic underlayers [S. Iwasaki and K. Takemura, IEEE Trans. Magn. 11, 1173 (1975); S. Iwasaki and Y. Nakamura, IEEE Trans. Magn. 14, 436 (1978); S...

Perpendicular recording media for hard disk drives

There are provided a magnetoresistance effect element, a magnetic head, a magnetic head assembly and a magnetic recording system, which have high sensitivity and high reliability. The magnetoresistance effect element has two ferromagnetic layers, a non-magnetic layer provided between the ferromagnetic layers, and a layer containing an oxide or nitride as a principal component, wherein the layer containing the oxide or nitride as the principal component contains a magnetic transition metal element which does not bond to oxygen and nitrogen and which is at least one of Co, Fe and Ni.

Magnetoresistance effect element

A thin film magnetic head includes an upper shield section, a lower shield section and a magnetoresistance device section between the upper shield section and the lower shield section. The magnetoresistance device section is connected to the upper shield section and the lower shield section through conductive layers. Current flows through the magnetoresistance device section via the upper shield and the lower shield.

Thin film magnetic head

A magnetoresistance effect element comprises: a magnetoresistance effect film, a pair of electrodes, and a phase separation layer. The magnetoresistance effect film includes a first ferromagnetic layer whose direction of magnetization is pinned substantially in one direction, a second ferromagnetic layer whose direction of magnetization changes in response to an external magnetic field, and an intermediate layer provided between the first and second ferromagnetic layers. The pair of electrodes are electrically coupled to the magnetoresistance effect film and configured to supply a sense current perpendicularly to a film plane of the magnetoresistance effect film. The phase separation layer is provided between the pair of electrodes. The phase separation layer has a first phase and a second phase formed by a phase separation in a solid phase from an alloy including a plurality of elements. One of the first and second phases includes at least one element selected from the group consisting of oxygen, nitrogen, fluorine and carbon in higher concentration than other of the first and second phases.

Magnetoresistance effect element, magnetic head and magnetic reproducing apparatus

The magnetic properties of both single-layered and multilayered Fe-C films formed by dual ion beam sputtering are studied. When the C concentration in Fe-C films increases, the relative permeability of the film increases and the coercivity decreases. The relative permeability of single-layered Fe-9at%C film with a magnetostriction constant nearly zero, is 550 at 5 MHz, even though that of pure Fe is only 150. When a multilayered film is made by alternating 5nm thick permalloy intermediate layers with 95nm thick Fe-C films, the soft magnetic properties of the resulting film show tremendous improvement. Multilayered Fe-9at%C film shows a relative permeability of 1400 and a coercivity of 200A/m. Compressive stress up to -2 × 109N/m2exists in this film. This stress can be relieved by heat treating the film in Ar, which improves the soft magnetic properties. The Fe-9at%C/permalloy multi-layered film annealed for 1 hour at 400°C shows a saturation magnetic flux density of 2.1T, a relative permeability of 3000 and a coercivity of 80 A/m.

Magnetic properties of multilayered Fe-C film formed by dual ion beam sputtering

Multilayered magnetic films of the invention comprising at least two unit magnetic films each of which has a thickness of from 0.05 to 0.9 μm and includes a plurality of ferromagnetic layers each having a thickness of from 0.01 to 0.2 μm and a 1 nm to 10 nm thick first intermediate layer consisting of a ferromagnetic, nonmagnetic or antiferromagnetic material and provided between adjacent ferromagnetic layers, and a second intermediate layer having a thickness of from 10 to 40 nm, consisting of a nonmagnetic or antiferromagnetic material and provided between the at least two unit magnetic films. The multilayered magnetic film is suitable as a pole of a thin-film magnetic head. An underlayer may be further provided between the magnetic film and a substrate whereby a multilayered magnetic film having good characteristics can be obtained.

Multilayered magnetic films and thin-film magnetic heads using the same as a pole

A multilayered ferromagnetic amorphous alloy film is constituted by a plurality of main ferromagnetic material alloy films of a ferromagnetic amorphous alloy laminated one upon another with a spacer ferromagnetic material layer interposed therebetween, the spacer ferromagnetic material layer being of a ferromagnetic material different from the ferromagnetic alloy. Also disclosed is a magnetic head employing the above-described multilayered film for, at least, a portion of a core thereof. The multilayered film has excellent magnetic characteristics and is easily patterned.

Multilayered ferromagnetic amorphous alloy film and magnetic head employing the same

A magnetic film structure comprises at least one magnetic film unit wherein a plurality of main magnetic films of 0.05 to 0.5 μm thickness made of a magnetic alloy containing iron or cobalt as principal constituent and having a high saturation magnetic induction of 10,000 gauss or more and a magnetostriction of 10-6 or less are laminated through intermediate magnetic films made of a magnetic material such as a nickel and iron alloy or amorphous magnetic alloy different from that of the main magnetic film and being so thin that the influence of coercive force of the intermediate magnetic film does not come out. A plurality of the magnetic film units are also laminated through non-magnetic insulating films. The magnetic film structure has high saturation magnetic induction and low coercive force.

Magnetic film structure

Ion implantation is conducted in a desired area(s) of the surface of a magnetic layer, and annealing of the layer is carried out to control the composition in that desired area(s). The control of the composition may be facilitated by applying a one-directional or rotating magnetic field during ion implantation. In preparing a magnetic head, a portion of a magnetic pole at least on one side thereof in close proximity to a magnetic recording medium is formed into an iron or iron-based magnetic alloy film, at least part of which is subjected to ion implantation and annealing.

Shigekazu Otomo

Papers

Magnetic properties of multilayered Fe-C film formed by dual ion beam sputtering

Multilayered magnetic films and thin-film magnetic heads using the same as a pole

Multilayered ferromagnetic amorphous alloy film and magnetic head employing the same

Magnetic film structure

Process for preparing magnetic layer and magnetic head prepared using the same