Sandisk 3d LLC

Sandisk Technologies Inc.

Sandisk Corporation

Michael Konevecki

Usha Raghuram

Steven J Radigan

Vance Dunton

Natalie Nguyen

Paul Wai Kie Poon

Yung-Tin Chen

Raghuveer S Makala

April Dawn Schricker

Steve Radigan

Andrew J Walker

Tanmay Kumar

Maitreyee Mahajani

Steven Patrick Maxwell

Samuel Vance Dunton

Sucheta Nallamothu

Brad Herner

Luke Zhang

S Brad Herner

Michael L Chan

Mark Harold Clark

Chuanbin Pan

Paul Poon

Xiao Li

Abhijit Bandyopadhyay

Zhida Lan

Andy Fu

Venkatagirish Nagavarapu

Three-dimensional (3D) non-volatile memory arrays having a vertically-oriented thin film transistor (TFT) select device and methods of fabricating such a memory are described. The vertically-oriented TFT may be used as a vertical bit line selection device to couple a global bit line to a vertical bit line. A select device pillar includes a body and upper and lower source/drain regions. At least one gate is separated horizontally from the select device pillar by a gate dielectric. The gates overlie the global bit lines with one or more insulating layers therebetween to provide adequate isolation between the gates and the global bit lines. Processes for fabricating the vertical TFT select devices utilize a gate dielectric and optional dielectric bases to provide isolation between the gates and bit lines.

Vertical bit line non-volatile memory systems and methods of fabrication

A memory device includes at least one memory cell. The at least one memory cell includes a steering element, a resistive memory element, and a tunneling dielectric element located between the steering element and the resistive memory element.

Resistive random access memory containing a steering element and a tunneling dielectric element

A three-dimensional (3D) non-volatile memory array is provided having multiple word line layers stacked vertically with interleaving insulating layers over a vertically-oriented thin film transistor (TFT). The vertically-oriented TFT is used as a bit line selection device to couple a global bit line to a vertical bit line formed in a trench between portions of the word line and insulating layer stack. The word line layers are recessed horizontally to form recesses relative to the vertical bit line trench. The horizontal recesses provide spatial separation between memory cell areas and surfaces exposed during process steps. A memory material is formed conformally within the recesses, followed by a thin protective film. The film protects the memory material during etching to expose the vertical TFT for contact to the vertical bit line. Methods of fabricating arrays including recessed memory cell areas are provided.

Vertical bit line non-volatile memory with recessed word lines

A method of making a semiconductor device includes providing an insulating layer containing a plurality of openings, forming a first semiconductor layer in the plurality of openings in the insulating layer and over the insulating layer, and removing a first portion of the first semiconductor layer, such that first conductivity type second portions of the first semiconductor layer remain in lower portions of the plurality of openings in the insulating layer, and upper portions of the plurality of openings in the insulating layer remain unfilled. The method also includes forming a second semiconductor layer in the upper portions of the plurality of openings in the insulating layer and over the insulating layer, and removing a first portion of the second semiconductor layer located over the insulating layer. The second conductivity type second portions of the second semiconductor layer remain in upper portions of the plurality of openings in the insulating layer to form a plurality of pillar shaped diodes in the plurality of openings.

Pillar devices and methods of making thereof

A memory cell is provided that includes a steering element, a reversible resistance-switching element coupled to the steering element and a silicide-forming metal layer disposed between the steering element and the reversible resistance-switching element. The reversible resistance-switching element includes tantalum, and is formed using a selective deposition process. Numerous other aspects are provided.

Memory cell that employs a selectively deposited reversible resistance-switching element and methods of forming the same

Methods in accordance with the invention involve patterning and etching very small dimension pillars, such as in formation of a memory array in accordance with the invention. When dimensions of pillars become very small, the photoresist pillars used to pattern them may not have sufficient mechanical strength to survive the photoresist exposure and development process. Using methods according to the present invention, these photoresist pillars are printed and developed larger than their intended final dimension, such that they have increased mechanical strength, then are shrunk to the desired dimension during a preliminary etch performed before the etch of underlying material begins.

Patterning of submicron pillars in a memory array

A method is provided for forming a monolithic three dimensional memory array. The method includes forming a first memory level above a substrate, and monolithically forming a second memory level above the first memory level. The first memory level is formed by forming first substantially parallel conductors extending in a first direction, forming first pillars above the first conductors, each first pillar including a first conductive layer or layerstack above a vertically oriented diode, the first pillars formed in a single photolithography step, depositing a first dielectric layer above the first pillars, etching first trenches in the first dielectric layer, the first trenches extending in a second direction. After etching, a lowest point in the trenches is above a lowest point of the first conductive layer or layerstack, and the first conductive layer or layerstack does not include a resistivity-switching metal oxide or nitride. Numerous other aspects are provided.

Methods for protecting patterned features during trench etch

Memory cells, and methods of forming such memory cells are provided that include a steering element coupled to a carbon-based reversible resistivity-switching material. In particular embodiments, methods in accordance with this invention etch a carbon nano-tube ('CNT') film formed over a substrate, the methods including coating the substrate with a masking layer, patterning the masking layer, and etching the CNT film through the patterned masking layer using a non-oxygen based chemistry. Other aspects are also described.

Methods for etching carbon nano-tube films for use in non-volatile memories

A method of making a device includes forming a first photoresist layer over a sacrificial layer, patterning the first photoresist layer to form first photoresist features, rendering the first photoresist features insoluble to a solvent, forming a second photoresist layer over the first photoresist features, patterning the second photoresist layer to form second photoresist features, forming a spacer layer over the first and second photoresist features, etching the spacer layer to form spacer features and to expose the first and second photoresist features, forming third photoresist features between the spacer features, removing the spacer features, and patterning the sacrificial layer using the first, second and third photoresist features as a mask to form sacrificial features.

Patterning method for high density pillar structures

A method for fabricating a 3-D monolithic memory device in which a via and trench are etched using an amorphous carbon hard mask. The via extends in multiple levels of the device as a multi-level vertical interconnect. The trench extends laterally, such as to provide a word line or bit line for memory cells, or to provide other routing paths. A dual damascene process can be used in which the via is formed first and the trench is formed second, or the trench is formed first and the via is formed second. The technique is particularly suitable for deep via applications, such as for via depths of greater than 1 &#x3bc;m. A dielectric antireflective coating, optionally with a bottom antireflective coating, can be used to etch an amorphous carbon layer to provide the amorphous carbon hard mask.

Dual damascene with amorphous carbon for 3D deep via/trench application

A method of making a non-volatile memory device includes providing a substrate having a substrate surface, and forming a non-volatile memory array over the substrate surface. The non-volatile memory array includes an array of semiconductor diodes, and each semiconductor diode of the array of semiconductor diodes is disposed substantially parallel to the substrate surface.

Diode array and method of making thereof

In some aspects, a method of forming a memory cell is provided that includes (1) forming a first conductor above a substrate; (2) forming a diode above the first conductor; (3) forming a reversible resistance-switching element above the first conductor using a selective deposition process; and (4) forming a second conductor above the diode and the reversible resistance-switching element. Numerous other aspects are provided.

Growing community of inventors

San Jose, CA, United States of America

Michael Konevecki