Sandisk Technologies Inc.

Shuji Minagawa

Takaaki Iwai

Hisakazu Otoi

Hiroyuki Ogawa

James K Kai

Jayavel Pachamuthu

Tuan Duc Pham

Yao-Sheng Lee

Masatoshi Nishikawa

Michiaki Sano

Masanori Tsutsumi

Kiyohiko Sakakibara

Seiji Shimabukuro

Yoshitaka Otsu

Jongsun Sel

Kensuke Yamaguchi

Yuji Fukano

Sayako Nagamine

Shigehiro Fujino

Masanori Terahara

Junpei Kanazawa

Cheng-Chung Chu

Fabo Yu

Koichiro Nagata

Shigeyuki Sugihara

Takashi Orimoto

Masahiro Yaegashi

Hajime Kimura

Hao Ding

Memory openings and backside openings are formed through an alternating stack of insulating layers and sacrificial material layers with patterned stepped surfaces and an overlying retro-stepped dielectric material portion. The backside openings may be formed in rows with shape modifications in staircase regions to provide more lateral elongation in areas with lesser layers of the alternating stack. Non-circular horizontal cross-sectional shapes for the backside openings in the staircase regions allow formation of the backside opening with less shape distortion. Memory opening fill structures are formed in the memory openings, and the sacrificial material layers are replaced with electrically conductive layers using the backside openings as conduits for an etchant and for a deposition precursor material. The electrically conductive layers are isotropically recessed around each backside opening to form width-modulated cavities, which is filled with width-modulated insulating wall structures.

Three-dimensional memory device having double-width staircase regions and methods of manufacturing the same

An array of memory stack structures extends through an alternating stack of insulating layers and electrically conductive layers over a substrate. An array of drain select level assemblies including cylindrical electrode portions is formed over the alternating stack with the same periodicity as the array of memory stack structures. A drain select level isolation strip including dielectric materials can be formed between a neighboring pair of drain select level assemblies employing the drain select level assemblies as a self-aligning template. Alternatively, cylindrical electrode portions can be formed around an upper portion of each memory stack structure. Strip electrode portions are formed on the cylindrical electrode portions after formation of the drain select level isolation strip.

Three-dimensional memory device having on-pitch drain select gate electrodes and method of making the same

Memory openings and backside openings are formed through an alternating stack of insulating layers and sacrificial material layers over a substrate. Memory opening fill structures are formed in the memory openings, and sacrificial backside opening fill structures are formed in the backside openings. Cavities are formed in volumes of the backside openings by removing the sacrificial backside opening fill structures. Remaining portions of the sacrificial material layers are replaced with material portions including electrically conductive layers. Each electrically conductive layer is formed as a continuous material layer including holes around the backside openings. Each electrically conductive layer is singulated into a plurality of electrically conductive strips by isotropically recessing the electrically conductive layers around each backside opening. Width-modulated cavities including expanded volumes of the backside openings are formed, and are filled with width-modulated insulating wall structures.

Three-dimensional memory device employing discrete backside openings and methods of making the same

Memory openings and support openings can be formed through an alternating stack of insulating layers and sacrificial material layers. A set of dielectric layers and at least one semiconductor material layer can be sequentially deposited in each of the memory openings and the support openings. The at least one semiconductor material layer is removed from inside the support openings, while the at least one semiconductor material layer is not removed from inside the memory openings. Memory stack structures and support pillar structures are formed in the memory openings and the support openings, respectively. The sacrificial material layers are replaced with electrically conductive layers. Removal of the at least one semiconductor material layer from the support pillar structures reduces or eliminates leakage current through the support pillar structures.

Three-dimensional memory device with leakage reducing support pillar structures and method of making thereof

An alternating stack of insulating layers and sacrificial material layers are formed over a substrate. Memory stack structures are formed through the alternating stack. A backside trench is formed and the sacrificial material layers are replaced with electrically conductive layers. After formation of an insulating spacer in the trench, an epitaxial pedestal structure is grown from a semiconductor portion underlying the backside trench. A source region is formed by introducing dopants into the epitaxial pedestal structure and an underlying semiconductor portion during and/or after epitaxial growth. Alternatively, the backside trench can be formed concurrently with formation of memory openings. An epitaxial pedestal structure can be formed concurrently with formation of epitaxial channel portions at the bottom of each memory opening. After formation and subsequent removal of a dummy trench fill structure in the backside trench, a source region is formed by introducing dopants into the epitaxial pedestal structure.

Epitaxial source region for uniform threshold voltage of vertical transistors in 3D memory devices

Memory openings and support openings are formed through an alternating stack of insulating layers and spacer material layers over a semiconductor substrate. Deposition of a semiconductor material in the support openings during formation of epitaxial channel portions in the memory openings is prevented by Portions of the semiconductor substrate that underlie the support openings are converted into impurity-doped semiconductor material portions. During selective growth of epitaxial channel portions from the semiconductor substrate within the memory openings, growth of a semiconductor material in the support openings is suppressed due to the impurity species in the impurity-doped semiconductor material portions. Memory stack structures and support pillar structures are subsequently formed over the epitaxial channel portions and in the support openings, respectively. The support pillar structures are formed with an outermost dielectric layer to prevent a leakage path to electrically conductive layers to be subsequently formed.

Method of suppressing epitaxial growth in support openings and three-dimensional memory device containing non-epitaxial support pillars in the support openings

A multilevel structure includes a stack of an alternating plurality of electrically conductive layers and insulator layers located over a semiconductor substrate, and an array of memory stack structures located within memory openings through the stack. An epitaxial semiconductor pedestal is provided, which is in epitaxial alignment with a single crystalline substrate semiconductor material in the semiconductor substrate and has a top surface within a horizontal plane located above a plurality of electrically conductive layers within the stack. The contact via structures for the semiconductor devices on the epitaxial semiconductor pedestal can extend can be less than the thickness of the stack.

Vertical NAND device containing peripheral devices on epitaxial semiconductor pedestal

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Yokkaichi, Japan

Shuji Minagawa