Sandisk Technologies Inc.

Junichi Ariyoshi

Raghuveer S Makala

George Matamis

Xiaolong Hu

Keisuke Shigemura

Johann Alsmeier

Yanli Zhang

Rahul Sharangpani

Masanori Tsutsumi

Michiaki Sano

Shinsuke Yada

Sateesh Koka

Daxin Mao

Zhenyu Lu

Naohiro Hosoda

Tomohiro Kubo

Yuji Fukano

Tadashi Nakamura

Wenguang Shi

Jiyin Xu

Koji Miyata

Takashi Inomata

Nobuo Hironaga

Kazuki Kajitani

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

A memory device contains a stack of insulating layers and electrically conductive word line layers, at least one first drain select gate electrode located over the stack and extending through a first drain select transistor and a second drain select transistor, at least one second drain select gate electrode located between the first drain select electrode and the stack, and extending through a third drain select transistor and a fourth drain select transistor. The first drain select transistor and the third drain select transistor are located in a first NAND memory string. The second drain select transistor and the fourth drain select transistor are located in a second NAND memory string different from the first NAND memory string. The first drain select transistor has a higher threshold voltage than the second drain select transistor. The third drain select transistor has a lower threshold voltage than the fourth drain select transistor.

Three-dimensional memory device containing multi-threshold-voltage drain select gates and method of making the same

Electrical short caused by misalignment of source select level contact via structure and support pillar structures can be prevented by modifying the pattern of the support pillar structures such that the support pillar structures are omitted from the area in which source select gate contact via structures are formed. The insulating layer at the level overlying the source select level electrically conductive layer can have a sufficient thickness to prevent deformation during formation of the backside recesses. A minimum lateral separation distance between the source select level contact via structure and the support pillar structures is greater than any minimum lateral separation distance between the word line level contact via structures and the support pillar structures.

Three-dimensional memory device with short-free source select gate contact via structure and method of making the same

A monolithic three-dimensional memory device includes a first alternating stack of first insulating layers and first electrically conductive layers located over a top surface of a substrate, an insulating cap layer overlying the first alternating stack, a second alternating stack of second insulating layers and second electrically conductive layers and overlying the insulating cap layer, memory openings extending through the second alternating stack, the insulating cap layer, and the first alternating stack, memory stack structures located within the memory openings, and annular spacers located within the insulating cap layer and laterally surrounding a respective one of the memory stack structures.

Three-dimensional memory device containing annular etch-stop spacer and method of making thereof

A semiconductor die includes a pair of first alternating stacks of first portions of insulating layers and electrically conductive layers located over a semiconductor substrate, groups of memory stack structures vertically extending through a respective one of the pair of the first alternating stacks, a pair of second alternating stacks of second portions of the insulating layers and dielectric material layers laterally adjoined to a respective one of the first alternating stacks, such that each second portion of the insulating layers is connected to a respective one of the first portions of the insulating layers, and at least one seal ring structure laterally enclosing, and laterally spaced from, the pair of first alternating stacks, and contacting at least a first sidewall of each of the pair of second alternating stacks.

Compact three-dimensional memory device having a seal ring and methods of manufacturing the same

A three-dimensional memory device includes an alternating stack of insulating layers and electrically conductive layers located over a substrate, the alternating stack having a memory array region and a contact region containing stepped surfaces, and memory stack structures having a semiconductor channel and a memory film extending through the memory array region of the alternating stack. The electrically conductive layers include a drain select gate electrode and word lines, where the drain select gate electrode is thicker than each of the word lines.

Three-dimensional memory device having select gate electrode that is thicker than word lines and method of making thereof

Memory-opening semiconductor material portions and support opening fill structures can be simultaneously formed through a first alternating stack of first insulating layers and first sacrificial material layers. Dopant species that retard or prevent etching of the material of the support opening fill structures can be implanted into an upper portion of each support opening fill structure, while memory-opening semiconductor material portions are masked from implantation. After formation of a second alternating stack and second openings therethrough, the sacrificial material of the memory-opening semiconductor material portions is removed while the support opening fill structures is not removed. Damage to the first sacrificial material layers during formation of the staircase contact region and resulting leakage paths from word lines to the substrate through support pillar structures can be avoided or reduced by not removing the support opening fill structures.

Multilevel memory stack structure employing stacks of a support pedestal structure and a support pillar structure

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

Resistance of a semiconductor channel in three-dimensional memory stack structures can be reduced by forming a metal-semiconductor alloy region between a vertical semiconductor channel and a horizontal semiconductor channel located within a substrate. The metal-semiconductor alloy region can be formed by recessing a portion of the semiconductor material layer in the semiconductor substrate underneath a memory opening after formation of a memory film, selectively depositing a metallic material in the recess region, depositing a vertical semiconductor channel, and reacting the deposited metallic material with an adjacent portion of the semiconductor material layer and the vertical semiconductor channel. A sacrificial dielectric material layer can be formed on the memory film prior to the selective deposition of the metallic material. The vertical semiconductor channel can be formed in a single deposition process, thereby eliminating any interface therein and minimizing the resistance of the vertical semiconductor channel.

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Yokkaichi, Japan

Junichi Ariyoshi