Panasonic Corporation

Matsushita Electric Industrial Co., Ltd.

Panasonic Intellectual Property Management Co., Ltd.

Yoshihiko Kanzawa

Takeshi Takagi

Tohru Saitoh

Shunsaku Muraoka

Satoru Mitani

Katsuya Nozawa

Koji Katayama

Kazuhiko Shimakawa

Minoru Kubo

Satoru Fujii

Akira Asai

Zhiqiang Wei

Koichiro Yuki

Yoshihiro Hara

Takahiro Kawashima

Teruhito Ohnishi

Ryoko Miyanaga

Ryotaro Azuma

Kenji Toyoda

Junko Iwanaga

Yo Ichikawa

Ken Idota

Koichi Osano

Teruhito Oonishi

Yoshikazu Katoh

Haruyuki Sorada

Takeki Ninomiya

Gaku Sugahara

Mitsuteru Iijima

Yuichiro Ikeda

Yuuichirou Ikeda

Kouji Katayama

Zhiquiang Wei

Provided is a method for driving a variable resistance nonvolatile storage element that can improve the information holding capability. The method includes: determining whether or not a current that flows through the nonvolatile storage element is larger than or equal to a first verify level IRL (Verify); determining whether or not a current that flows through the nonvolatile storage element is smaller than or equal to a second verify level IRH (Verify); and determining that the nonvolatile storage element is in the second resistance state when the current that flows through the nonvolatile storage element is smaller than a current reference level Iref, and determining that the nonvolatile storage element is in the first resistance state when the current is larger than the current reference level Iref, the current reference level Iref satisfying (IRL (Verify)+IRH (Verify))/2&#x3c;Iref&#x3c;IRL (Verify).

Method for driving nonvolatile storage element, and nonvolatile storage device

Provided is a method for reading data from a variable resistance nonvolatile storage element, where the operation for reading data is less susceptible to a fluctuation phenomenon of resistance values in reading the data. The method includes: detecting a current value Ithat flows through the nonvolatile storage element that can be in a low resistance state RL and a high resistance state RH, with application of a fixed voltage; and determining that (i) the nonvolatile storage element is in a high resistance state when the current value Idetected in the detecting is smaller than a current reference level Iref, and (ii) the nonvolatile storage element is in a low resistance state when the current value Idetected in the detecting is larger than the reference level Iref, the current reference level Iref being defined by (IRL+IRH)/2&#x3c;Iref&#x3c;IRL.

Method for reading data from nonvolatile storage element, and nonvolatile storage device

A variable resistance nonvolatile storage device which includes (i) a semiconductor substrate, (ii) a variable resistance element having: lower and upper electrodes; and a variable resistance layer whose resistance value reversibly varies based on voltage signals each of which has a different polarity and is applied between the electrodes, and (iii) a MOS transistor formed on the substrate, wherein the variable resistance layer includes: oxygen-deficient transition metal oxide layers having compositions MOand MO(where x&#x3c;y) and in contact with the electrodes respectively, a diffusion layer region is connected with the lower electrode to form a memory cell, the region serving as a drain upon application of a voltage signal which causes a resistance change to high resistance state in the variable resistance layer.

Variable resistance nonvolatile storage device and method of forming memory cell

A variable resistance nonvolatile memory device includes a plurality of memory cells in each of which a variable resistance element and a current steering element having two terminals are connected in series. Additionally, a current limit circuit limits a first current flowing in a direction for changing the memory cells to a low resistance state, and a boost circuit increases, when one of the memory cells changes to the low resistance state, the first current in a first period before the memory cell changes to the low resistance state.

Variable resistance nonvolatile memory device and programming method for same

A nonvolatile memory device () includes a variable resistance nonvolatile memory element () and a control circuit (). The control circuit () determines whether a resistance value of the nonvolatile memory element () in a high resistance state is equal to or greater than a predetermined threshold value. Moreover, if the resistance value of the nonvolatile memory element () in the high resistance state is smaller than the threshold value, the control circuit () applies a first voltage (VL) to the nonvolatile memory element () to change a resistance state of the nonvolatile memory element () from the high resistance state to the low resistance state. Moreover, if the resistance value of the nonvolatile memory element () in the high resistance state is equal to or greater than the threshold value, the control circuit () applies to the nonvolatile memory element () a second voltage (VL) an absolute value of which is smaller an absolute value of the first voltage (VL) to change the resistance state of the nonvolatile memory element () from the high resistance state to the low resistance state.

Nonvolatile memory device and method for programming nonvolatile memory element

A nonvolatile memory element includes: a first electrode layer; a second electrode layer; and a variable resistance layer which is placed between the electrode layers, and whose resistance state reversibly changes between a high resistance state and a low resistance state based on a polarity of a voltage applied between the electrode layers. The variable resistance layer is formed by stacking a first oxide layer including an oxide of a first transition metal and a second oxide layer including an oxide of a second transition metal which is different from the first transition metal. At least one of the following conditions is satisfied: (1) a dielectric constant of the second oxide layer is larger than a dielectric constant of the first oxide layer; and (2) a band gap of the second oxide layer is smaller than a band gap of the first oxide layer.

Nonvolatile memory element and nonvolatile memory device

A nonvolatile memory element of the present invention comprises a first electrode (), a second electrode (); a resistance variable layer () which is interposed between the first electrode () and the second electrode () and is configured to switch a resistance value reversibly in response to an electric signal applied between the electrodes () and (), and the resistance variable layer () has at least a multi-layer structure in which a first hafnium-containing layer having a composition expressed as HfO(0.9&#x2266;x&#x2266;1.6), and a second hafnium-containing layer having a composition expressed as HfO(1.8&#x3c;y&#x3c;2.0) are stacked together.

Nonvolatile memory element, manufacturing method thereof, and nonvolatile semiconductor device incorporating nonvolatile memory element

A variable resistance nonvolatile storage device which includes (i) a semiconductor substrate (), (ii) a variable resistance element () having: lower and upper electrodes (,); and a variable resistance layer () whose resistance value reversibly varies based on voltage signals each of which has a different polarity and is applied between the electrodes (,), and (iii) a MOS transistor () formed on the substrate (), wherein the variable resistance layer () includes: oxygen-deficient transition metal oxide layers (-,-) having compositions MOand MO(where x&#x3c;y) and in contact with the electrodes (,) respectively, and a diffusion layer region () is connected with the lower electrode () to form a memory cell (), the region () serving as a drain of the transistor () upon application of a voltage signal which causes a resistance change to high resistance state in the variable resistance layer ().

A semiconductor device includes: a semiconductor substrate in which a trench is formed; a source region and a drain region each of which is buried in the trench and contains an impurity of the same conductive type; a semiconductor FIN buried in the trench and provided between the source and drain regions; a gate insulating film provided on a side surface of the semiconductor FIN as well as the upper surface of the semiconductor FIN; and a gate electrode formed on the gate insulating film.

Semiconductor device and method for fabricating the same

The variable resistance nonvolatile storage device includes a memory cell () that is formed by connecting in series a variable resistance element () including a variable resistance layer () which reversibly changes based on electrical signals each having a different polarity and a transistor () including a semiconductor substrate () and two N-type diffusion layer regions (), wherein the variable resistance layer () includes an oxygen-deficient oxide of a transition metal, lower and upper electrodes () are made of materials of different elements, a standard electrode potential Vof the lower electrode (), a standard electrode potential Vof the upper electrode (), and a standard electrode potential Vof the transition metal satisfy V&#x3c;Vand V&#x3c;V, and the lower electrode () is connected with the N-type diffusion layer region (), the electrical signals being applied between the lower and upper electrodes ().

Variable resistance nonvolatile storage device with oxygen-deficient oxide layer and asymmetric substrate bias effect

A nonvolatile memory element includes first and second electrodes, and a resistance variable layer disposed therebetween. At least one of the first and second electrodes includes a platinum-containing layer. The resistance variable layer includes a first oxygen-deficient transition metal oxide layer which is not physically in contact with the platinum-containing layer and a second oxygen-deficient transition metal oxide layer which is disposed between the first oxygen-deficient transition metal oxide layer and the platinum-containing layer and is physically in contact with the platinum-containing layer. When oxygen-deficient transition metal oxides included in the first and second oxygen-deficient transition metal oxide layers are expressed as MO, and MO, respectively, x&#x3c;y is satisfied. The platinum-containing layer has a thickness which is not less than 1 nm and not more than 23 nm.

Nonvolatile memory element having a thin platinum containing electrode

A nonvolatile memory element comprises a first electrode layer (), a second electrode (), and a resistance variable layer () which is disposed between the first electrode layer () and the second electrode layer (), a resistance value of the resistance variable layer varying reversibly according to electric signals having different polarities which are applied between the electrodes (), (), wherein the resistance variable layer () has a first region comprising a first oxygen-deficient tantalum oxide having a composition represented by TaOx (0&#x3c;x&#x3c;2.5) and a second region comprising a second oxygen-deficient tantalum oxide having a composition represented by TaOy (x&#x3c;y&#x3c;2.5), the first region and the second region being arranged in a thickness direction of the resistance variable layer.

Nonvolatile memory element, manufacturing method thereof, and nonvolatile semiconductor apparatus using the nonvolatile memory element

A nonvolatile resistance variable memory device () includes memory cells (M, M, . . . ) in each of which a variable resistance element (R, R, . . . ) including a variable resistance layer placed between and in contact with a first electrode and a second electrode, and a current steering element (D, D, . . . ) including a current steering layer placed between and in contact with a third electrode and a fourth electrode, are connected in series, and the device is driven by a first LR drive circuit () via a current limit circuit () to decrease resistance of the variable resistance element while the device is driven by a second HR drive circuit () to increase resistance of the variable resistance element, thus using the current limit circuit () to make a current for decreasing resistance of the variable resistance element lower than a current for increasing resistance of the variable resistance element.

Variable resistance nonvolatile memory device

Provided is a programming method for improving the retention characteristics of information in a variable resistance nonvolatile memory element. The method includes: a first writing process of applying a first voltage Vhaving a first polarity to set the variable resistance nonvolatile storage element to a low resistance state LR indicating first logic information (S); a second writing process of applying a second voltage Vhaving a second polarity different from the first polarity to set the variable resistance nonvolatile storage element to a first high resistance state HR(S); and a partial write process of applying a third voltage Vhaving the first polarity so as to set the variable resistance layer to a second high resistance state HRindicating second logic information different from the first logic information (S). Here, |V|&#x3c;|V|, and resistance values in HR, HR, LR are greater in this order.

Method of programming nonvolatile memory element

A nonvolatile memory element of the present invention comprises a first electrode (); a second electrode (); and a resistance variable layer () which is disposed between the first electrode () and the second electrode (), a resistance value of the resistance variable layer being changeable in response to electric signals which are applied between the first electrode () and the second electrode (), wherein the first electrode and the second electrode comprise materials which are made of different elements.

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Osaka, Japan

Yoshihiko Kanzawa