Sandisk Technologies Inc.

Xiaolong Hu

Johann Alsmeier

Zhenyu Lu

Wenguang Shi

Henry Chien

Daxin Mao

Junichi Ariyoshi

Jiyin Xu

Koji Miyata

Yingda Dong

Yanli Zhang

Christopher John Petti

James K Kai

Gerrit Jan Hemink

Man Lung Mui

George Matamis

Tong Zhang

Masatoshi Nishikawa

Wei Zhao

Shinsuke Yada

Kensuke Yamaguchi

Hiro Kinoshita

Hiroaki Iuchi

Kazutaka Yoshizawa

Yusuke Yoshida

Sayako Nagamine

Akira Nakada

Takashi Kashimura

A three-dimensional memory device includes alternating stacks of insulating strips and electrically conductive strips located over a substrate and laterally spaced apart among one another by vertically undulating trenches. The vertically undulating trenches have a greater lateral extent at levels of the electrically conductive strips than at levels of the insulating strips. An interlaced two-dimensional array of memory stack assemblies and dielectric pillar structures are located in the vertically undulating trenches. Each memory stack assembly includes a vertical semiconductor channel and a pair of memory films including a respective pair of convex outer sidewalls that contact, or are spaced by a uniform distance from, concave sidewalls of the electrically conductive strips. Local electrical field at laterally protruding tips of the vertical semiconductor channels are enhanced due to the geometric effect provided by the concave sidewalls of the electrically conductive strips to facilitate faster program and erase operations.

Three-dimensional flat NAND memory device including concave word lines and method of making the same

A three-dimensional memory device includes an alternating stack of insulating layers and electrically conductive layers located over a substrate. An insulating fill material layer and drain select gate electrodes are located over the alternating stack. A group of memory stack structures extends through the alternating stack, and is arranged as rows of memory stack structures. Each memory stack structure is entirely encircled laterally by a respective one of the drain select gate electrodes. The insulating fill material layer includes a drain select level isolation structure extending between neighboring rows of memory stack structures and including a pair of sidewalls containing a respective laterally alternating sequence of planar vertical sidewall portions and concave vertical sidewall portions, and a drain select level field portion adjoined to the drain select level isolation portion.

Three-dimensional memory device with self-aligned drain select level isolation structures and method of making thereof

Techniques for forming 3D memory arrays are disclosed. Memory openings are filled with a sacrificial material, such as silicon or nitride. Afterwards, a replacement technique is used to remove nitride from an ONON stack and replace it with a conductive material such as tungsten. Afterwards, memory cell films are formed in the memory openings. The conductive material serves as control gates of the memory cells. The control gate will not suffer from corner rounding. ONON shrinkage is avoided, which will prevent control gate shrinkage. Block oxide between the charge storage region and control gate may be deposited after control gate replacement, so the uniformity is good. Block oxide may be deposited after control gate replacement, so TiN adjacent to control gates can be thicker to prevent fluorine attacking the insulator between adjacent control gates. Therefore, control gate to control gate shorting is prevented.

Forming 3D memory cells after word line replacement

An alternating stack of insulator layers and spacer material layers is formed over a substrate. Stepped surfaces are formed in a contact region in which contact via structures are to be subsequently formed. An epitaxial semiconductor pedestal can be formed by a single epitaxial deposition process that is performed after formation of the stepped surfaces and prior to formation of memory openings, or a combination of a first epitaxial deposition process performed prior to formation of memory openings and a second epitaxial deposition process performed after formation of the memory openings. The epitaxial semiconductor pedestal can have a top surface that is located above a topmost surface of the alternating stack. The spacer material layers are formed as, or can be replaced with, electrically conductive layers. Backside contact via structures can be subsequently formed.

Three dimensional memory device with epitaxial semiconductor pedestal for peripheral transistors

A multi-tier memory device is formed over a substrate such that memory stack structures extend through an alternating stack of insulating layers and electrically conductive layers within each tier. Bit lines are formed between an underlying tier having drain regions over semiconductor channels and an overlying tier having drain regions under semiconductor channel, such that the bit lines are shared between the underlying tier and the overlying tier. Source lines can be formed over each tier in which source regions overlie semiconductor channels and drain regions. If another tier is present above the source lines, the source lines can be shared between two vertically neighboring tiers.

Multi tier three-dimensional memory devices including vertically shared bit lines

Non-volatile storage devices and methods for fabricating non-volatile storage device are described. Sidewalls of the memory cells and their associated word line may be covered with silicon oxide. Silicon nitride covers the silicon oxide adjacent to the word lines, which may provide protection for the word lines during fabrication. However, silicon nitride can trap charges, which can degrade operation if the trapped charges are near a charge trapping region of a memory cell. Thus, the silicon nitride does not cover the silicon oxide adjacent to charge storage regions of the memory cells, which can improve device operation. For example, memory cell current may be increased. Techniques for forming such a device are also disclosed. One aspect includes a method that uses a sacrificial material to control formation of a silicon nitride layer when forming a memory device.

Non-volatile storage having oxide/nitride sidewall

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Yokkaichi, Japan

Xiaolong Hu