Intermolecular, Inc.

Kabushiki Kaisha Toshiba

Sandisk 3D LLC

Crystal Solar, Inc.

Intermoecular, Inc.

Vidyut Gopal

Imran Hashim

Yun Yu Wang

Takeshi Yamaguchi

Hieu T Pham

Dipankar Pramanik

Tim Minvielle

Randall Higuchi

Hong Sheng Yang

Tony P Chiang

Jinhong Tong

Chien-Lan Hsueh

Zhendong Hong

Tony Chiag

Ananda H Kumar

Minh Le

Milind Ganesh Weling

Robert A Huertas

Tirunelveli Subramaniam Ravi

Minh Anh Nguyen

Albert Sanghyup Lee

Ryan C Clarke

David Chi

Frederick Carlos Fulgenico

Methods for producing RRAM resistive switching elements having reduced forming voltage include doping to create oxygen deficiencies in the dielectric film. Oxygen deficiencies in a dielectric film promote formation of conductive pathways.

Method for forming a doped metal oxide for use in resistive switching memory elements

Provided are nonvolatile memory assemblies each including a resistive switching layer and current steering element. The steering element may be a transistor connected in series with the switching layer. Resistance control provided by the steering element allows using switching layers requiring low switching voltages and currents. Memory assemblies including such switching layers are easier to embed into integrated circuit chips having other low voltage components, such as logic and digital signal processing components, than, for example, flash memory requiring much higher switching voltages. In some embodiments, provided nonvolatile memory assemblies operate at switching voltages less than about 3.0V and corresponding currents less than 50 microamperes. A memory element may include a metal rich hafnium oxide disposed between a titanium nitride electrode and doped polysilicon electrode. One electrode may be connected to a drain or source of the transistor, while another electrode is connected to a signal line.

Embedded nonvolatile memory elements having resistive switching characteristics

Provided are resistive random access memory (ReRAM) cells and methods of fabricating thereof. A stack including a defect source layer, a defect blocking layer, and a defect acceptor layer disposed between the defect source layer and the defect blocking layer may be subjected to annealing. During the annealing, defects are transferred in a controllable manner from the defect source layer to the defect acceptor layer. At the same time, the defects are not transferred into the defect blocking layer thereby creating a lowest concentration zone within the defect acceptor layer. This zone is responsible for resistive switching. The precise control over the size of the zone and the defect concentration within the zone allows substantially improvement of resistive switching characteristics of the ReRAM cell. In some embodiments, the defect source layer includes aluminum oxynitride, the defect blocking layer includes titanium nitride, and the defect acceptor layer includes aluminum oxide.

Confined defect profiling within resistive random memory access cells

Embodiments of the invention generally relate to nonvolatile memory devices and methods for manufacturing such memory devices. The methods for forming improved memory devices, such as a ReRAM cells, provide optimized, atomic layer deposition (ALD) processes for forming a metal oxide film stack which contains at least one hard metal oxide film (e.g., metal is completely oxidized or substantially oxidized) and at least one soft metal oxide film (e.g., metal is less oxidized than hard metal oxide). The soft metal oxide film is less electrically resistive than the hard metal oxide film since the soft metal oxide film is less oxidized or more metallic than the hard metal oxide film. In one example, the hard metal oxide film is formed by an ALD process utilizing ozone as the oxidizing agent while the soft metal oxide film is formed by another ALD process utilizing water vapor as the oxidizing agent.

Atomic layer deposition of metal oxides for memory applications

Embodiments of the invention generally relate to nonvolatile memory devices, such as a ReRAM cells, and methods for manufacturing such memory devices, which includes optimized, atomic layer deposition (ALD) processes for forming metal oxide film stacks. The metal oxide film stacks contain a metal oxide coupling layer disposed on a metal oxide host layer, each layer having different grain structures/sizes. The interface disposed between the metal oxide layers facilitates oxygen vacancy movement. In many examples, the interface is a misaligned grain interface containing numerous grain boundaries extending parallel to the electrode interfaces, in contrast to the grains in the bulk film extending perpendicular to the electrode interfaces. As a result, oxygen vacancies are trapped and released during switching without significant loss of vacancies. Therefore, the metal oxide film stacks have improved switching performance and reliability during memory cell applications compared to traditional hafnium oxide based stacks of previous memory cells.

Atomic layer deposition of metal oxide materials for memory applications

Embodiments of the invention include nonvolatile memory elements and memory devices comprising the nonvolatile memory elements. Methods for forming the nonvolatile memory elements are also disclosed. The nonvolatile memory element comprises a first electrode layer, a second electrode layer, and a plurality of layers of an oxide disposed between the first and second electrode layers. One of the oxide layers has linear resistance and substoichiometric composition, and the other oxide layer has bistable resistance and near-stoichiometric composition. Preferably, the sum of the two oxide layer thicknesses is between about 20 &#x212b; and about 100 &#x212b;, and the oxide layer with bistable resistance has a thickness between about 25% and about 75% of the total thickness. In one embodiment, the oxide layers are formed using reactive sputtering in an atmosphere with controlled flows of argon and oxygen.

Transition metal oxide bilayers

A method of fabricating a resistive random access memory (ReRAM) cell may include forming a set of nanolaminate structures over an electrode, such that each structure includes at least one first element oxide layer and at least one second element oxide layer. The overall set is operable as a resistive switching layer in a ReRAM cell. In this set, an average atomic ratio of the first element to the second element is different in at least two nanolaminate structures. This ratio may be less in nanolaminate structures that are closer to electrodes than in the middle nanolaminate structures. Alternatively, this ratio may increase from one end of the set to another. The first element may be less electronegative than the second elements. The first element may be hafnium, while the second element may be one of zirconium, aluminum, titanium, tantalum, or silicon.

Controlling composition of multiple oxides in resistive switching layers using atomic layer deposition

Provided are semiconductor devices, such as resistive random access memory (ReRAM) cells, that include current limiting layers formed from doped metal oxides and/or nitrides. These current limiting layers may have resistivities of at least about 1 Ohm-cm. This resistivity level is maintained even when the layers are subjected to strong electrical fields and/or high temperature annealing. In some embodiments, the breakdown voltage of a current limiting layer may be at least about 8V. Some examples of such current limiting layers include titanium oxide doped with niobium, tin oxide doped with antimony, and zinc oxide doped with aluminum. Dopants and base materials may be deposited as separate sub-layers and then redistributed by annealing or may be co-deposited using reactive sputtering or co-sputtering. The high resistivity of the layers allows scaling down the size of the semiconductor devices including these layer while maintaining their performance.

Resistive random access memory cells having doped current limiting layers

A nonvolatile memory element is disclosed comprising a first electrode, a near-stoichiometric metal oxide memory layer having bistable resistance, and a second electrode in contact with the near-stoichiometric metal oxide memory layer. At least one electrode is a resistive electrode comprising a sub-stoichiometric transition metal nitride or oxynitride, and has a resistivity between 0.1 and 10 &#x3a9;cm. The resistive electrode provides the functionality of an embedded current-limiting resistor and also serves as a source and sink of oxygen vacancies for setting and resetting the resistance state of the metal oxide layer. Novel fabrication methods for the second electrode are also disclosed.

Multifunctional electrode

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Sunnyvale, CA, United States of America

Vidyut Gopal