Intermolecular, Inc.

Kabushiki Kaisha Toshiba

Sandisk 3d LLC

Chien-Lan Hsueh

Randall Higuchi

Yun Yu Wang

Takeshi Yamaguchi

Vidyut Gopal

Mihir Tendulkar

Tim Minvielle

Tony P Chiang

Jinhong Tong

Chen-An Chen

James Tsung

Nan Lu

Albert Sanghyup Lee

Martin Romero

Provided are resistive random access memory (ReRAM) cells having switching layers that include hafnium, aluminum, oxygen, and nitrogen. The composition of such layers is designed to achieve desirable performance characteristics, such as low current leakage as well as low and consistent switching currents. In some embodiments, the concentration of nitrogen in a switching layer is between about 1 and 20 atomic percent or, more specifically, between about 2 and 5 atomic percent. Addition of nitrogen helps to control concentration and distribution of defects in the switching layer. Also, nitrogen as well as a combination of two metals helps with maintaining this layer in an amorphous state. Excessive amounts of nitrogen reduce defects in the layer such that switching characteristics may be completely lost. The switching layer may be deposited using various techniques, such as sputtering or atomic layer deposition (ALD).

Resistive switching layers including Hf-Al-O

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

Apparatus for high productivity combinatorial (HPC) processing of semiconductor substrates and HPC methods are described. An apparatus includes a showerhead and two or more pressure-controlled one-way valves connected to the showerhead and used for controlling flow of different processing gases into the showerhead. The pressure-controlled one-way valves are not externally controlled by any control systems. Instead, these valves open and close in response to preset conditions, such as pressure differentials and/or flow differentials. One example of such pressure-controlled one-way valves is a check valve. These valves generally allow the flow only in one direction, i.e., into the showerhead. Furthermore, lack of external controls and specific mechanical designs allow positioning these pressure-controlled one-way valves in close proximity to the showerhead thereby reducing the dead volume between the valves and the showerhead and also operating these valves at high temperatures.

High productivity combinatorial processing using pressure-controlled one-way valves

Compound layers, such as metal silicon nitrides, are formed by ALD or CVD from precursors with incompatible reaction temperature ranges. The substrate is held at a temperature within the lower reaction temperature range (e.g., that of a metal precursor). The low-temperature precursor and its reactant react to form an ALD monolayer or thin CVD layer. The high-temperature precursor and its reactant are pulsed in the chamber, and the substrate is irradiated with ultraviolet light. The ultraviolet light adds energy to the system to overcome the reaction barrier despite the substrate temperature being below the minimum reaction temperature of the high-temperature precursor.

Low-temperature deposition of nitrides by UV-assisted ALD or CVD

Provided are resistive random access memory (ReRAM) cells and methods of fabricating them using metal organic chemical vapor deposition (MOCVD). Specifically, MOCVD is used to form an embedded resistor that includes two different nitrides. The first nitride may be more conductive than the second nitride. The concentrations of these nitrides may vary throughout the thickness of the embedded resistor. This variability may be achieved by changing flow rates of MOCVD precursors during formation of the embedded resistor. The second nitride may be concentrated in the middle of the embedded resistor, while the first nitride may be present at interface surfaces of the embedded resistor. As such, the first nitride protects the second nitride from exposure to other components and/or environments and prevents oxidation of the second nitride. Controlling the distribution of the two nitrides within the embedded resistor allows using new materials and achieving consistent performance of the embedded resistor.

Metal organic chemical vapor deposition of embedded resistors for ReRAM cells

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

A nonvolatile memory device contains a resistive switching memory element with improved device switching performance and lifetime by custom tailoring the average concentration of defects in the resistive switching film and methods of forming the same. The nonvolatile memory element includes a first electrode layer, a second electrode layer, and a resistive switching layer disposed between the first electrode layer and the second electrode layer. The resistive switching layer comprises a first sub-layer and a second sub-layer, wherein the first sub-layer has more defects than the first sub-layer. A method includes forming a first sub-layer on the first electrode layer by a first ALD process and forming a second sub-layer on the first sub-layer by a second ALD process, where the first sub-layer has a different amount of defects than the second sub-layer.

Using saturated and unsaturated ALD processes to deposit oxides as ReRAM switching layer

Provided are resistive random access memory (ReRAM) cells and methods of fabricating thereof using metal organic chemical vapor deposition (MOCVD). Specifically, the MOCVD is used to form a resistive switching layer including oxides of at least two elements. The resistive switching layer may have a variable composition throughout its thickness, which may be achieved by dynamically varying flow rates of metal organic precursors during MOCVD of the resistive switching layer. In some embodiments, the first element may be a transition metal, while the second element may be a component forming an insulating oxide. The second element may be concentrated in the middle of the resistive switching layer between its bottom and top sides and may not be present at either one of these sides. Such distribution of materials allows controlling the size and composition of a switching zone within the resistive switching layer and reducing power needed for switching.

Metal organic chemical vapor deposition of resistive switching layers for ReRAM cells

A nonvolatile resistive memory element includes a novel switching layer and methods of forming the same. The switching layer includes a material having bistable resistance properties and formed by bonding silicon to oxygen or nitrogen. The switching layer may include at least one of SiO, SiON, or SiN. Advantageously, the SiO, SiON, and SiNgenerally remain amorphous after thermal anneal processes are used to form the devices, such as ReRAM devices.

Nonvolatile resistive memory element with a silicon-based switching layer

Provided are resistive random access memory (ReRAM) cells and methods of fabricating thereof. A ReRAM cell includes an embedded resistor and resistive switching layer connected in series. The embedded resistor prevents excessive electrical currents through the resistive switching layer, especially when the resistive switching layer is switched into its low resistive state, thereby preventing over-programming. The embedded resistor includes aluminum, nitrogen, and one or more additional metals (other than aluminum). The concentration of each component is controlled to achieve desired resistivity and stability of the embedded resistor. In some embodiments, the resistivity ranges from 0.1 Ohm-centimeter to 40 Ohm-centimeter and remains substantially constant while applying an electrical field of up 8 mega-Volts/centimeter to the embedded resistor. The embedded resistor may be made from an amorphous material, and the material is operable to remain amorphous even when subjected to typical annealing conditions.

Metal aluminum nitride embedded resistors for resistive random memory access cells

Provided are resistive random access memory (ReRAM) cells and methods of fabricating thereof. A ReRAM cell includes an embedded resistor and a resistive switching layer connected in series with this resistor. The resistor is configured to prevent over-programming of the cell by limiting electrical currents through the resistive switching layer. Unlike the resistive switching layer, which changes its resistance in order to store data, the embedded resistor maintains a substantially constant resistance during operation of the cell. The embedded resistor is formed from tantalum nitride and silicon nitride. The atomic ratio of tantalum and silicon may be specifically selected to yield resistors with desired densities and resistivities as well as ability to remain amorphous when subjected to various annealing conditions. The embedded resistor may also function as a diffusion barrier layer and prevent migration of components between one of the electrodes and the resistive switching layer.

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A single TiON film is used to form a ReRAM device by varying the oxygen and nitrogen content throughout the device to form the electrodes and switching layer. A ReRAM device that can be formed in a single deposition chamber is also disclosed. The ReRAM device can be formed by forming a first titanium nitride layer, forming a titanium oxynitride-titanium oxide-titanium oxynitride layer, and then forming a second titanium nitride.

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Campbell, CA, United States of America

Chien-Lan Hsueh