Patent application number | Description | Published |
20090273964 | NONVOLATILE SEMICONDUCTOR MEMORY DEVICE - A nonvolatile semiconductor memory device comprises: a two terminal structured variable resistive element, wherein resistive characteristics defined by current-voltage characteristics at both ends transit between low and high resistance states stably by applying a voltage satisfying predetermined conditions to the both ends, a transition from the low resistance state to the high resistance state occurs by applying a voltage of a first polarity whose absolute value is at or higher than a first threshold voltage, and the reverse transition occurs by applying a voltage of a second polarity whose absolute value is at or higher than a second threshold voltage; a load circuit connected to the variable resistive element in series having an adjustable load resistance; and a voltage generation circuit for applying a voltage to both ends of a serial circuit; wherein the variable resistive element can transit between the states by adjusting a resistance of the load circuit. | 11-05-2009 |
20100073983 | NONVOLATILE SEMICONDUCTOR MEMORY DEVICE AND WRITING METHOD OF THE SAME - A nonvolatile semiconductor memory device comprises a memory cell array composed of a plurality of memory cells each including a variable resistance element in which a resistance characteristic is changed by applying a voltage to the both ends, and information related to the resistance characteristic can be stored; a load circuit connected to one terminal of the variable resistance element in series; and a voltage generation circuit for applying a voltage to both ends of a series circuit. The variable resistance element selectively transits to one resistance characteristic selected from at least three different resistance characteristics when the voltage generated from the voltage generation circuit is applied under the transition condition set by changing any one or both of the load resistance characteristic of the load circuit and the voltage generation condition from the voltage generation circuit, and can store information having at least three values. | 03-25-2010 |
20100172170 | VARIABLE RESISTIVE ELEMENT, MANUFACTURING METHOD FOR SAME, AND NON-VOLATILE SEMICONDUCTOR MEMORY DEVICE - Provided is a variable resistive element which performs high speed and low power consumption operation. The variable resistive element comprises a metal oxide layer between first and second electrodes wherein electrical resistance between the first and second electrodes reversibly changes in accordance with application of electrical stress across the first and second electrodes. The metal oxide layer has a filament, which is a current path where the density of a current flowing between the first and second electrodes locally increases. A portion including at least the vicinity of an interface between the certain electrode, which is one or both of the first and second electrodes, and the filament, on an interface between the certain electrode and the metal oxide layer is provided with an interface oxide which is an oxide of at least one element included in the certain electrode and different from the oxide of the metal oxide layer. | 07-08-2010 |
Patent application number | Description | Published |
20090147558 | VARIABLE RESISTANCE ELEMENT, METHOD FOR PRODUCING THE SAME, AND NONVOLATILE SEMICONDUCTOR STORAGE DEVICE - The variable resistance element of the present invention is a variable resistance element having an electrode, the other electrode, and a metal oxide material sandwiched between the electrodes and having an electrical resistance, between the electrodes, changing reversibly in response to a voltage applied between the electrodes. The variable resistance element further includes, inside the metal oxide material, a low resistance material having a lower electrical resistance than the metal oxide material and being out of contact with at least either one of the electrodes. This makes it possible to reduce a forming voltage for providing a conductive section inside the metal oxide material, without causing a leakage current to increase. | 06-11-2009 |
20100085142 | VARIABLE RESISTOR ELEMENT, MANUFACTURING METHOD THEREOF, AND MEMORY DEVICE PROVIDED WITH IT - A variable resistor element comprising a first electrode, a second electrode, and a variable resistor positioned between the first and second electrodes, and changing in electric resistance when a voltage pulse is applied between the both electrodes, has posed problems that it has a restriction of having to use noble metal electrodes as an electrode material and is not compatible with a conventional CMOS process. A variable resistor element using an oxynitride of transition metal element as a variable resistor exhibits a stable switching operation, is satisfactory in data retaining characteristics, and requires a small programming current. Since it does not necessarily require noble metal as an electrode material, it is high in compatibility with the existing CMOS process and easy to produce. It can be formed by a simple step of forming a variable resistor material into a film by oxidizing a lower electrode surface consisting of conductive nitride. | 04-08-2010 |
Patent application number | Description | Published |
20090096568 | VARIABLE RESISTANCE ELEMENT, AND ITS MANUFACTURING METHOD - Provided are a variable resistive element having a configuration that the area of an electrically contributing region in a variable resistor body is smaller than the area defined by an upper electrode or a lower electrode, and a method for manufacturing the variable resistive element. The cross section of a current path, in which an electric current flows through between the two electrodes via the variable resistor body at the time of applying the voltage pulse to between the two electrodes, is formed with a line width of narrower than that of any of the two electrodes and of smaller than a minimum work dimension regarding manufacturing processes, so that its area can be made smaller than that of the electrically contributing region in the variable resistive element of the prior art. | 04-16-2009 |
20090097300 | VARIABLE RESISTANCE ELEMENT, ITS MANUFACTURING METHOD AND SEMICONDUCTOR MEMORY DEVICE COMPRISING THE SAME - Provided is a variable resistance element capable of performing a stable resistance switching operation and having a favorable resistance value retention characteristics, comprising a variable resistor | 04-16-2009 |
20090200640 | VARIABLE RESISTIVE ELEMENT, AND ITS MANUFACTURING METHOD - A variable resistive element comprising a configuration that an area of an electrically contributing region of a variable resistor body is finer than that constrained by an upper electrode or a lower electrode and its manufacturing method are provided. A bump electrode material is formed on a lower electrode arranged on a base substrate. The bump electrode material is contacted to a variable resistor body at a surface different from a contact surface to the lower electrode. The variable resistor body is contacted to an upper electrode at a surface different from a contact surface to the bump electrode material. Thus, a cross point region between the bump electrode material (the variable resistor body) and the upper electrode becomes an electrically contributing region of the variable resistor body, and then an area thereof can be reduced compared with that of the region regarding the conventional variable resistive element. | 08-13-2009 |
20090231083 | Variable resistor element and its manufacturing method - A variable resistance element comprises a variable resistor of strongly-correlated material sandwiched between two metal electrodes, and the electric resistance between the metal electrodes varies when a voltage pulse is applied between the metal electrodes. Such a switching operation as the ratio of electric resistance between low and high resistance states is high can be attained by designing the metal electrodes and variable resistor appropriately based on a definite switching operation principle. Material and composition of the first electrode and variable resistor are set such that metal insulator transition takes place on the interface of the first electrode in any one of two metal electrodes and the variable resistor by applying a voltage pulse. Two-phase coexisting phase of metal and insulator phases can be formed in the vicinity of the interface between the variable resistor and first electrode by the work function difference between the first electrode and variable resistor. | 09-17-2009 |
20140027703 | VARIABLE RESISTIVE ELEMENT, AND ITS MANUFACTURING METHOD - A variable resistive element comprising a configuration that an area of an electrically contributing region of a variable resistor body is finer than that constrained by an upper electrode or a lower electrode and its manufacturing method are provided. A bump electrode material is formed on a lower electrode arranged on a base substrate. The bump electrode material is contacted to a variable resistor body at a surface different from a contact surface to the lower electrode. The variable resistor body is contacted to an upper electrode at a surface different from a contact surface to the bump electrode material. Thus, a cross point region between the bump electrode material (the variable resistor body) and the upper electrode becomes an electrically contributing region of the variable resistor body, and then an area thereof can be reduced compared with that of the region regarding the conventional variable resistive element. | 01-30-2014 |