Hitachi, Ltd.

Tohoku University

Hitachi Metals, Ltd.

Other

Centre National De La Recherche Scientifique

Renesas Technology Corp.

Nippon Columbia Co., Ltd.

Université Paris Sud Xi

Kenchi Ito

Hiromasa Takahashi

Jun Hayakawa

Riichiro Takemura

Takayuki Kawahara

Kazumi Kawamoto

Takeshi Shimano

Hideo Ohno

Yasuo Hira

Hiroyuki Awano

Hidemi Sato

Yooji Maruyama

Atsuko Fukushima

Takeshi Sakata

Tetsuo Endoh

Hideyuki Matsuoka

Shoji Ikeda

Masataka Shiba

Hideo Sato

Katsuya Miura

Susumu Soeya

Satoru Hanzawa

Katsuro Watanabe

Susumu Ogawa

Hiroaki Honjo

Akira Inagaki

Masaaki Niwa

Kiyoo Itoh

Masaki Yamada

Minoru Yoshida

Hiroyuki Yamamoto

Shunsuke Fukami

Toshimichi Shintani

Sumio Hosaka

Yoshiaki Kawato

Ryuichi Funatsu

Fumihiro Matsukura

Kohei Ito

Fumio Nitanda

Kyota Watanabe

Mathias Bersweiler

Hiroshi Momiji

Akira Arimoto

Masafumi Mochizuki

Hideki Saga

Tetsuya Nishida

Yumiko Anzai

Yoshito Tsunoda

Kimio Tatsuno

Takeshi Harada

Tetsuo Andou

Kimitoshi Etoh

Tomohiro Okada

Naoya Kanda

Hiroaki Nemoto

Kazuo Ono

Masahiko Takahashi

Masaru Muranishi

Masayoshi Sato

Takashi Ishigaki

Kimio Nakamura

Satoshi Makio

Mieko Ishii

Hiroshi Asao

Osamu Komoda

Hajime Koyanagi

Claude Chappert

Atsushi Kikukawa

Hisao Kurosawa

Youichi Inoue

Kazuhiko Nakano

Sadahiko Miura

Sten Helmfrid

Takashi Saito

Paul Crozat

Masakazu Muraguchi

Jörg Wunderlich

Kazutami Kawamoto

Masazumi Sato

Yasuhiro Furukawa

Hisae Sasaki

Thibault Devolder

Joo-von Kim

A method and a system for measuring the thermal stability factor of a magnetic tunnel junction device, a semiconductor integrated circuit, and a production management method for the semiconductor integrated circuit, capable of measuring the thermal stability factors of individual devices in a relatively short period of time and quickly performing quality control during material development and at a production site. A meter measures change in resistance value of an evaluation MTJ for a predetermined period while causing a predetermined current to flow into the evaluation MTJ maintained at a predetermined temperature. An analyzer calculates a time constant in which a low-resistance state is maintained and a time constant in which a high-resistance state is maintained from the measured change in resistance value. A thermal stability factor of the evaluation MTJ is calculated on the basis of the calculated time constants and the predetermined current flowing into the evaluation MTJ.

Method and system for measuring thermal stability factor of magnetic tunnel junction device, semiconductor integrated circuit, and production management method for semiconductor integrated circuit

A magnetoresistance effect element includes first and second magnetic layers having a perpendicular magnetization direction, and a first non-magnetic layer disposed adjacent to the first magnetic layer and on a side opposite to a side on which the second magnetic layer is disposed. An interfacial perpendicular magnetic anisotropy exists at an interface between the first magnetic layer and the first non-magnetic layer, and the anisotropy causes the first magnetic layer to have a magnetization direction perpendicular to the surface of the layers. An atomic fraction of all magnetic elements to all magnetic and non-magnetic elements included in the second magnetic layer is smaller than that of the first magnetic layer.

Magnetoresistance effect element and magnetic memory

A method for producing a magnetic memory includes: forming a magnetic film having a non-magnetic layer between a first magnetic layer and a second magnetic layer on a substrate having an electrode layer; performing annealing treatment at a first treatment temperature in a state where a magnetic field is applied in a direction perpendicular to a film surface of the first or the second magnetic layer in vacuum; forming a magnetic tunnel junction element; forming a protective film protecting the magnetic tunnel junction element; a formation accompanied by thermal history, in which a constituent element of a magnetic memory is formed after the protective film formation on the substrate; and implementing annealing treatment at a second treatment temperature lower than the first treatment temperature on the substrate in an annealing treatment chamber, in vacuum or inert gas wherein no magnetic field is applied.

Method for producing magnetic memory comprising magnetic tunnel junction element

A magnetoresistance effect element includes first and second magnetic layers having a perpendicular magnetization direction, and a first non-magnetic layer disposed adjacent to the first magnetic layer and on a side opposite to a side on which the second magnetic layer is disposed. An interfacial perpendicular magnetic anisotropy exists at an interface between the first magnetic layer and the first non-magnetic layer, and the anisotropy causes the first magnetic layer to have a magnetization direction perpendicular to the surface if the layers. The second magnetic layer has a saturation magnetization lower than that of the first magnetic layer, and an interfacial magnetic anisotropy energy density (K) at the interface between the first magnetic layer and the first non-magnetic layer is greater than that of an interface between the first non-magnetic layer and second magnetic layers if being disposed adjacent each other.

As a technique for attaining a reduction in power consumption, there is a technique for reducing power consumption using a spin wave. No specific proposal concerning spin wave generation, spin wave detection, and a latch technique for information has been made. A device applies an electric field to a first electrode of a nonmagnetic material using a thin line-shaped stacked body including a first ferromagnetic layer and a nonmagnetic layer to thereby generate a spin wave in the first ferromagnetic layer, and detects a phase or amplitude of the spin wave propagated in the first ferromagnetic layer using a second electrode of a ferromagnetic material with a magnetoresistance effect.

Spin wave device and logic circuit using spin wave device

There is provided a magnetic memory with using a magnetoresistive effect element of a spin-injection magnetization reversal type, in which a multi-value operation is possible and whose manufacturing and operation are simple. A preferred aim of this is solved by providing two or more magnetoresistive effect elements which are electrically connected in series to each other and by selecting one of the series-connected elements depending on a direction of a current carried in the series-connected elements, a magnitude thereof, and an order of the current thereof for performing the writing operation. For example, it is solved by differentiating plane area sizes of the respective magnetoresistive effect elements which have the same film structure from each other so as to differentiate resistance change amounts caused by respective magnetization reversal and threshold current values required for respective magnetization reversal from each other.

Magnetic memory, method of manufacturing the same, and method of driving the same

A magnetoresistive effect element uses a perpendicularly magnetized material and has a high TMR ratio. Intermediate layers composed of an element metal having a melting point of 1600&#xb0; C. or an alloy containing the metal on an outside of a structure consisting of a CoFeB layer, an MgO barrier layer, and a CoFeB layer. By inserting the intermediate layers, crystallization of the CoFeB layer during annealing is advanced from an MgO (001) crystal side, so that the CoFeB layer has a crystalline orientation in bcc (001).

Magnetoresistive effect element, magnetic memory cell using same, and random access memory

A spin-wave waveguide includes a ferromagnetic thin film resembling a wire in shape. A part of the ferromagnetic thin film, large in film thickness, is formed at one end of the ferromagnetic thin film, and a part of the ferromagnetic thin film, small in film thickness, and a part of the ferromagnetic thin film, large in film thickness, are alternately formed on the same plane, for at least not less than one cycle. A part of the ferromagnetic thin film, large in film thickness, is formed at the other end of the ferromagnetic thin film, wherein an insulating film, and an electrode film are stacked in this order on the ferromagnetic thin film in the part of the ferromagnetic thin film, large in film thickness.

Spin-wave waveguide and spin wave operation circuit

Provided is a magnetic random access memory to which spin torque magnetization reversal is applied, the magnetic random access memory being thermal stable in a reading operation and also being capable of reducing a current in a wiring operation. A magnetoresistive effect element formed by sequentially stacking a fixed layer, a nonmagnetic barrier layer, and a recording layer is used as a memory element. The recording layer adopts a laminated ferrimagnetic structure. The magnetic memory satisfies the expression M(t/w)&#x3e;|J|&#x3e;(2kT&#x394;)/S, in which kis a Boltzmann constant, T is an operating temperature of the magnetic memory, S is an area parallel to a film surface of the magnetoresistive effect element, t and Mare respectively a film thickness and a saturated magnetization of the ferromagnetic layer having a smaller film thickness among two ferromagnetic layers which are constituent members of the laminated ferrimagnetic structure, w is a length of a short side of the recording layer, &#x394; is a thermal stability index of the magnetic memory, and Jis exchange coupling energy acting between the two ferromagnetic layers of the recording layer.

Magnetic memory

To write information on a memory cell of SPRAM formed of an MOS transistor and a tunnel magnetoresistive element, the memory cell is supplied with a current in a direction opposite to a direction of a current required for writing the information on the memory cell, and then, the memory cell is supplied with a current required for writing. In this manner, even when the same information is sequentially written on the memory cell, since the currents in the two directions are caused to flow in pairs in the tunnel magnetoresistive element of the memory cell each time information is rewritten, deterioration of a film that forms the tunnel magnetoresistive element can be suppressed. Therefore, reliability of the SPRAM can be improved.

Semiconductor storage device

A memory for which writing is conducted by using a unidirectional write current. Currents which differ in current pulse width are applied to a magnetoresistance element in a film thickness direction of the magnetoresistance element consisting of a first ferromagnetic layer having a fixed magnetization direction, a second ferromagnetic layer having a variable magnetization direction, a third ferromagnetic layer having a variable magnetization direction, a first non-magnetic layer located between the first ferromagnetic layer and the second ferromagnetic layer, and a second non-magnetic layer located between the second ferromagnetic layer and the third ferromagnetic layer, to reverse a magnetization direction of either the second ferromagnetic layer or the third ferromagnetic layer by using a spin-transfer torque.

Unidirectional-current magnetization-reversal magnetoresistance element and magnetic recording apparatus

In MRAM using a spin-transfer torque switching, a sufficient writing operation with a small memory cell is realized, and a reading current is enlarged while a reading disturbance is suppressed. In the case where the free layer of the tunnel magneto-resistance element is located on the side of the bit line, using a PMOS transistor, and in the case where the fixed layer of the tunnel magneto-resistance element is located on the side of the bit line, using an NMOS transistor, an anti-parallel writing in a source grounding operation is performed. The reading and writing operation margin is improved by performing a reading operation in an anti-parallel writing direction.

Semiconductor device

In a memory using spin transfer torque, state of the spin is made unstable by applying a weak pulse before rewriting to reduce rewrite current. Reading of high-speed operation is performed with current in a regime where the current becomes non-linearly increases corresponding to the pulse width to suppress disturb. Further, fluctuation of respective memory cells is suppressed by a driving method setting the amount of spin constant by bit line charge to suppress read disturb.

A magnetic random access memory which employs spin torque magnetization reversal having a small write current value is applied. The memory includes: a switching element the conduction of which is controlled by a gate electrode, and three magnetoresistance effect elements connected to the switching element in series. Each magnetoresistance effect element may be a TMR element or a GMR element that includes a multilayered film composed of a fixed layer, a non-magnetic layer and a free layer. The central element serves as a storage element. The magnetoresistance effect elements are manufactured such that an absolute value of current necessary for changing a magnetization direction of at least one of the magnetoresistance effect elements located at both ends is larger than an absolute value of current necessary for changing a magnetization direction of the central magnetoresistance effect element.

Magnetic memory and method for writing to magnetic memory

An object of the present invention corrects fluctuation of a writing current between cells in a magnetic random access memory using spin torque magnetization reversal. The present invention includes a magneto-resistive effect element that is disposed between a bit line and a word line, a first variable resistance element that is connected to one end of the bit line, a second variable resistance element that is connected to the other end of the bit line, a first voltage applying unit that applies voltage to the first variable resistance element, and a second voltage applying unit that applies voltage to the second variable resistance element, when a writing operation is performed, an offset magnetic field is applied to a free layer of the magneto-resistive effect element by flowing a variable current between the first voltage applying unit and the second voltage applying unit based on a predetermined resistance value.

Spin torque magnetic memory and offset magnetic field correcting method thereof

Growing community of inventors

Kunitachi, Japan

Kenchi Ito