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

Patent metadata

Field	Value
Publication number	US-10014316-B2
Application number	US-201615296380-A
Country	US
Kind code	B2
Filing date	Oct 18, 2016
Priority date	Oct 18, 2016
Publication date	Jul 3, 2018
Grant date	Jul 3, 2018

Abstract

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.

First claim

What is claimed is:

1. A three-dimensional memory device comprising:
an alternating stack of insulating layers and electrically conductive layers located over a substrate;
memory stack structures extending through the alternating stack, wherein each of the memory stack structures comprises a memory film, a vertical semiconductor channel contacting an inner sidewall of the memory film, and a dielectric core contacting an inner sidewall of the vertical semiconductor channel; and
support pillar structures extending through the alternating stack and laterally spaced from the memory stack structures, wherein each of the support pillar structures comprises a dielectric layer stack and a dielectric fill material portion that contacts an inner sidewall of the dielectric layer stack; wherein:
an epitaxial channel portion is disposed between each vertical semiconductor channel and a semiconductor material portion of the substrate; and
a tubular dielectric spacer laterally surrounds, and contacts, a respective epitaxial channel portion; and one of:
(i) a first feature wherein an epitaxial pedestal comprising a same material as the epitaxial channel portion is present between each dielectric fill material portion and the semiconductor material portion the substrate; and
a top surface of the epitaxial channel portion extends farther away from the semiconductor material portion of the substrate than a top surface of the epitaxial pedestal; or

(ii) a second feature wherein a bottom surface of each dielectric layer stack contacts a semiconductor oxide portion which contacts the semiconductor material portion of the substrate.

2. The three-dimensional memory device of claim 1 , wherein each dielectric layer stack and each memory film include an identical set of dielectric material layers.

3. The three-dimensional memory device of claim 2 , wherein the memory film comprises a backside blocking dielectric layer, a charge trapping layer, and a tunneling dielectric layer.

4. The three-dimensional memory device of claim 1 , wherein each dielectric core and each of the dielectric fill material portions extend through more than 50% of all layers within the alternating stack.

5. The three-dimensional memory device of claim 1 , wherein:
the dielectric fill material portions of the support pillar structures are more proximal to a top surface of the substrate than the dielectric cores are to the top surface of the substrate; and
the dielectric layer stacks are more proximal to the top surface of the substrate than the memory films are to the top surface of the substrate.

6. The three-dimensional memory device of claim 1 , wherein each of the memory films and the dielectric layer stacks extends above a horizontal plane including a top surface of a topmost electrically conductive layer within the alternating stack.

7. The three-dimensional memory device of claim 1 , wherein:
the alternating stack comprises a terrace region in which each electrically conductive layer other than a topmost electrically conductive layer within the alternating stack laterally extends farther than any overlying electrically conductive layer within the alternating stack;
the terrace region includes stepped surfaces of the alternating stack that continuously extend from a bottommost layer within the alternating stack to a topmost layer within the alternating stack; and
the support pillar structures extend through the stepped surfaces and through a retro-stepped dielectric material portion that overlies the stepped surfaces.

8. The three-dimensional memory device of claim 1 , wherein the three-dimensional memory device comprises the first feature.

9. The three-dimensional memory device of claim 1 , wherein the three-dimensional memory device comprises the second feature.

10. The three-dimensional memory device of claim 9 , wherein each semiconductor oxide portion contacts a bottom surface of a respective dielectric fill material portion, such that no epitaxial channel material is present in between the dielectric fill material portion and the semiconductor material portion.

11. The three-dimensional memory device of claim 1 , wherein:
the three-dimensional memory device comprises a monolithic three-dimensional NAND memory device;
the electrically conductive layers comprise, or are electrically connected to, a respective word line of the monolithic three-dimensional NAND memory device;
the substrate comprises a silicon substrate;
the monolithic three-dimensional NAND memory device comprises an array of monolithic three-dimensional NAND strings over the silicon substrate;
at least one memory cell in a first device level of the array of monolithic three-dimensional NAND strings is located over another memory cell in a second device level of the array of monolithic three-dimensional NAND strings;
the silicon substrate contains an integrated circuit comprising a driver circuit for the memory device located thereon;
the electrically conductive layers comprise a plurality of control gate electrodes having a strip shape extending substantially parallel to the top surface of the substrate, the plurality of control gate electrodes comprise at least a first control gate electrode located in the first device level and a second control gate electrode located in the second device level; and
the array of monolithic three-dimensional NAND strings comprises:
a plurality of semiconductor channels, wherein at least one end portion of each of the plurality of semiconductor channels extends substantially perpendicular to a top surface of the substrate, and
a plurality of charge storage elements, each charge storage element located adjacent to a respective one of the plurality of semiconductor channels.

12. A three-dimensional memory device comprising:
an alternating stack of insulating layers and electrically conductive layers located over a substrate;
memory stack structures extending through the alternating stack, wherein each of the memory stack structures comprises a memory film, a vertical semiconductor channel contacting an inner sidewall of the memory film, and a dielectric core contacting an inner sidewall of the vertical semiconductor channel; and
support pillar structures extending through the alternating stack and laterally spaced from the memory stack structures, wherein each of the support pillar structures comprises a dielectric layer stack and a dielectric fill material portion that contacts an inner sidewall of the dielectric layer stack; wherein:
the three-dimensional memory device comprises a monolithic three-dimensional NAND memory device;
the electrically conductive layers comprise, or are electrically connected to, a respective word line of the monolithic three-dimensional NAND memory device;
the substrate comprises a silicon substrate;
the monolithic three-dimensional NAND memory device comprises an array of monolithic three-dimensional NAND strings over the silicon substrate;
at least one memory cell in a first device level of the array of monolithic three-dimensional NAND strings is located over another memory cell in a second device level of the array of monolithic three-dimensional NAND strings;
the silicon substrate contains an integrated circuit comprising a driver circuit for the memory device located thereon;
the electrically conductive layers comprise a plurality of control gate electrodes having a strip shape extending substantially parallel to the top surface of the substrate, the plurality of control gate electrodes comprise at least a first control gate electrode located in the first device level and a second control gate electrode located in the second device level; and
the arra

Assignees

• Sandisk Technologies Llc

Inventors

• Yu Fabo
• Pachamuthu Jayavel
• Sel Jongsun
• Pham Tuan
• Chu Cheng-Chung
• Lee Yao-Sheng
• Yamaguchi Kensuke
• Terahara Masanori
• Minagawa Shuji

Classifications

• H10W10/0143

  comprising concurrently refilling multiple trenches having different shapes or dimensions · CPC title

• H10W10/17

  formed using trench refilling with dielectric materials, e.g. shallow trench isolations · CPC title

• H01L27/11556

  Electricity · mapped topic

• H01L27/11575 Primary

  Electricity · mapped topic

• H01L29/0649

  Electricity · mapped topic