Micron Technology Incorporated

Sandisk 3d LLC

Sandisk Technologies Inc.

Intel Corporation

Andrei Mihnea

Chun Chen

Paul J Rudeck

Kirk D Prall

Yung-Tin Chen

Andrew Bicksler

Jeffrey Alan Kessenich

William R Kueber

Roy E Scheuerlein

Akira Goda

Mark Alan Helm

George Samachisa

Li Xiao

Luca Giovanni Fasoli

Steven Patrick Maxwell

Chuanbin Pan

Kun Hou

Deepak Chandra Sekar

Vinod C Lakhani

Todd A Marquart

Abhijit Bandyopadhyay

Johann Alsmeier

Yanli Zhang

Peter Rabkin

Franz Kreupl

Xiying Costa

Devin M Batutis

Daniel Doyle

Chandu Gorla

In some embodiments, a memory array is provided that includes (1) a first memory cell having (a) a first conductive line; (b) a first bipolar storage element formed above the first conductive line; and (c) a second conductive line formed above the first bipolar storage element; and (2) a second memory cell formed above the first memory cell and having (a) a second bipolar storage element formed above the second conductive line; and (b) a third conductive line formed above the second bipolar storage element. The first and second memory cells share the second conductive line; the first bipolar storage element has a first storage element polarity orientation within the first memory cell; the second bipolar storage element has a second storage element polarity orientation within the second memory cell; and the second storage element polarity orientation is opposite the first storage element polarity orientation. Numerous other aspects are provided.

Multi-level memory arrays with memory cells that employ bipolar storage elements and methods of forming the same

Programming NAND strings in a 3D stacked storage device to a conductive state. Storage elements may be erased by raising their Vt and programmed by lowering their Vt. Programming may include applying a series of increasing voltages to selected bit lines until the selected memory cell is programmed. Unselected bit lines may be held at about ground, or close to ground. The selected word line may be grounded, or be held close to ground. Unselected word lines between the selected word line and the bit line may receive about the selected bit line voltage. Unselected word lines between the source line and the selected word line may receive about half the selected bit line voltage. Programming may be achieved without boosting channels of unselected NAND strings to inhibit them from programming. Therefore, program disturb associated with leakage of boosted channel potential may be avoided.

3D stacked non-volatile storage programming to conductive state

In some embodiments, a memory cell is provided that includes a metal-insulator-metal stack and a steering element coupled to the metal-insulator-metal stack. The metal-insulator-metal stack includes a first conductive layer, a reversible resistivity switching layer above the first conductive layer, and a second conductive layer above the reversible resistivity switching layer. The first conductive layer and/or the second conductive layer includes a first semiconductor material layer. The steering element includes the first semiconductor material layer. Numerous other aspects are provided.

Memory cells having storage elements that share material layers with steering elements and methods of forming the same

A memory cell is provided that includes a steering element, a metal-insulator-metal stack coupled in series with the steering element, and a conductor above the metal-insulator-metal stack. The steering element includes a diode having an n-region and a p-region. The metal-insulator-metal stack includes a reversible resistivity-switching material between a top electrode and a bottom electrode, and the top electrode includes a highly doped semiconductor material. The memory cell does not include a metal layer disposed between the metal-insulator-metal stack and the conductor. The bottom electrode includes the n-region or the p-region of the diode, and the reversible resistivity-switching material is directly adjacent the n-region or the p-region of the diode. Numerous other aspects are provided.

Embodiments of the present disclosure provide methods, devices, modules, and systems for operating memory cells. One method includes: performing an erase operation on a selected group of memory cells, the selected group including a number of reference cells and a number of data cells; performing a programming monitor operation on the number of reference cells as part of the erase operation; and determining a number of particular operating parameters associated with operating the number of data cells at least partially based on the programming monitor operation performed on the number of reference cells.

Method and devices for memory cell erasure with a programming monitor of reference cells

A carbon/tunneling-barrier/carbon diode and method for forming the same are disclosed. The carbon/tunneling-barrier/carbon may be used as a steering element in a memory array. Each memory cell in the memory array may include a reversible resistivity-switching element and a carbon/tunneling-barrier/carbon diode as the steering element. The tunneling-barrier may include a semiconductor or an insulator. Thus, the diode may be a carbon/semiconductor/carbon diode. The semiconductor in the diode may be intrinsic or doped. The semiconductor may be depleted when the diode is under equilibrium conditions. For example, the semiconductor may be lightly doped such that the depletion region extends from one end of the semiconductor region to the other end. The diode may be a carbon/insulator/carbon diode.

Carbon/tunneling-barrier/carbon diode

A storage system and method for forming a storage system that uses punch-through diodes as a steering element in series with a reversible resistivity-switching element is described. The punch-through diode allows bipolar operation of a cross-point memory array. The punch-through diode may have a symmetrical non-linear current/voltage relationship. The punch-through diode has a high current at high bias for selected cells and a low leakage current at low bias for unselected cells. Therefore, it is compatible with bipolar switching in cross-point memory arrays having resistive switching elements. The punch-through diode may be a N+/P&#x2212;/N+ device or a P+/N&#x2212;/P+ device.

Punch-through diode steering element

A punch-through diode and method of fabricating the same are disclosed herein. The punch-through diode may be used as a steering element in a memory device having a reversible resistivity-switching element. For example, a memory cell may include a reversible resistivity-switching element in series with a punch-through diode. The punch-through diode allows bipolar operation of a cross-point memory array. The punch-through diode may have a symmetrical non-linear current/voltage relationship. The punch-through diode has a high current at high bias for selected cells and a low leakage current at low bias for unselected cells. In other words, the ratio of Ion/Ioff is high. Therefore, the punch-through diode is compatible with bipolar switching in cross-point memory arrays having resistive switching elements.

Punch-through diode

Embodiments of the present disclosure provide methods, devices, modules, and systems for healing non-volatile memory cells. One method includes biasing a first select gate transistor coupled to a string of memory cells at a first voltage, biasing a second select gate transistor coupled to the string at a second voltage, applying a first healing voltage to a first edge word line in order to extract charge accumulated between the first select gate transistor and a first edge memory cell stack of the string, and applying a second healing voltage to a second edge word line in order to extract charge accumulated between the second select gate transistor and a second edge memory cell stack of the string.

Non-volatile memory cell healing

A memory cell in a 3-D read and write memory device has two bipolar resistance-switching layers with different respective switching currents. A low current resistance-switching layer can be switched in set and reset processes while a high current resistance-switching layer remains in a reset state and acts as a protection resistor to prevent excessively high currents on the low current resistance-switching layer. The low and high current resistance-switching layers can be of the same material such as a metal oxide, where the layers differ in terms of thickness, doping, leakiness, metal richness or other variables. Or, the low and high current resistance-switching layers can be of different materials, having one or more layers each. The high current resistance-switching layer can have a switching current which is greater than a switching current of the low current resistance-switching layer by a factor of at least 1.5 or 2.0, for instance.

Resistive random access memory with low current operation

Method for memory cell erasure with a programming monitor of reference cells

A method of making a NAND string includes forming a semiconductor layer over a major surface of a substrate, patterning the semiconductor layer into an elongated nanowire shaped channel extending substantially parallel to the major surface of the substrate, forming a tunneling dielectric layer over the channel, forming a plurality of charge storage regions over the tunneling dielectric layer and undercutting the channel using the plurality of charge storage regions as mask. The channel has a narrower width than each charge storage region width, and an overhanging portion of each of the plurality of charge storage regions overhangs the channel. The method also includes forming a blocking dielectric layer over the plurality of charge storage regions, such that the blocking dielectric layer fills a space below the overhanging portion of each of the plurality of charge storage regions and forming a plurality of control gates over the blocking dielectric layer.

Junctionless TFT NAND flash memory

In some embodiments, a memory cell is provided that includes a storage element formed from an MIM stack including (1) a first conductive layer; (2) an RRS layer formed above the first conductive layer; and (3) a second conductive layer formed above the RRS layer, at least one of the first and second conductive layers comprising a first semiconductor material layer. The memory cell includes a steering element coupled to the storage element, the steering element formed from the first semiconductor material layer of the MIM stack and one or more additional material layers. Numerous other aspects are provided.

A nonvolatile memory device with a first conductor extending in a first direction and a semiconductor element above the first conductor. The semiconductor element includes a source, a drain and a channel of a field effect transistor (JFET or MOSFET). The nonvolatile memory device also includes a second conductor above the semiconductor element, the second conductor extending in a second direction. The nonvolatile memory device also includes a resistivity switching material disposed between the first conductor and the semiconductor element or between the second conductor and the semiconductor element. The JFET or MOSFET includes a gate adjacent to the channel, and the MOSFET gate being self-aligned with the first conductor.

Growing community of inventors

Boise, ID, United States of America

Andrei Mihnea