Sandisk Technologies Inc.

Tsuyoshi Hada

James K Kai

Jayavel Pachamuthu

Murshed Chowdhury

Satoshi Shimizu

Hiro Kinoshita

Atsushi Suyama

Tomoyuki Obu

Marika Gunji-Yoneoka

Kazuyo Matsumoto

Daewung Kang

Luckshitha Suriyasena Liyanage

A planar material layer stack including a lower etch stop dielectric layer, a sacrificial semiconductor layer, and an upper etch stop dielectric layer is formed over a source semiconductor layer on a substrate. An alternating stack of insulating layers and spacer material layers is formed. The spacer material layers are formed as, or are subsequently replaced with, electrically conductive layers. An array of memory stack structures is formed. A source cavity is formed by removing the sacrificial semiconductor layer and portions of the memory films. Source strap structures are formed by a selective semiconductor deposition process on the vertical semiconductor channels and the source semiconductor layer. A dielectric fill material layer fills a remaining volume of the source cavity.

Three-dimensional memory device having discrete direct source strap contacts and method of making thereof

An alternating stack of insulating layers and spacer material layers is formed over a semiconductor substrate. Memory openings are formed through the alternating stack. An optional silicon-containing epitaxial pedestal and a memory film are formed in each memory opening. After forming an opening through a bottom portion of the memory film within each memory opening, a germanium-containing semiconductor layer and a dielectric layer is formed in each memory opening. Employing the memory film and the dielectric layer as a crucible, a liquid phase epitaxy anneal is performed to convert the germanium-containing semiconductor layer into a germanium-containing epitaxial channel layer. A dielectric core and a drain region can be formed over the dielectric layer. The germanium-containing epitaxial channel layer is single crystalline, and can provide a higher charge carrier mobility than a polysilicon channel.

Three-dimensional memory device having epitaxial germanium-containing vertical channel and method of making thereof

A method of fabricating a semiconductor device, such as a three-dimensional monolithic NAND memory string, includes providing an opening having a different sidewall material exposed on a sidewall of the opening than a bottom material exposed on a bottom of the opening, selectively forming a sacrificial material on the bottom of the opening but not on the sidewall of the opening, selectively forming a first layer on the sidewall of the opening but not on the sacrificial material located on the bottom of the opening, and selectively removing the sacrificial material to expose the bottom material on the bottom of the opening such that the first layer remains on the sidewall of the opening.

Method of selective filling of memory openings

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Yokkaichi, Japan

Tsuyoshi Hada