IP Library Granted Patent US 11,665,893
Granted Patent B2
US 11,665,893 · App. 15/255,967 · Granted May 30, 2023

Methods and apparatuses having strings of memory cells including a metal source

Inventors: Zhenyu Lu (Boise, ID); Roger W. Lindsay (Boise, ID); Andrew Bicksler (Nampa, ID); Yongjun Jeff Hu (Boise, ID); Haitao Liu (Boise, ID)
Assignee: Micron Technology, Inc.
H01L27/11556H01L23/5283H01L27/11524H01L29/456H01L29/66825H01L29/7926
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Quick Facts
Patent No.
US 11,665,893
App. No.
15/255,967
Granted
May 30, 2023
Kind
B2
Abstract

Methods for forming a string of memory cells, an apparatus having a string of memory cells, and a system are disclosed. A method for forming the string of memory cells comprises forming a metal silicide source material over a substrate. The metal silicide source material is doped. A vertical string of memory cells is formed over the metal silicide source material. A semiconductor material is formed vertically and adjacent to the vertical string of memory cells and coupled to the metal silicide source material.

Claims (40)

1. An apparatus comprising:

a plurality of alternating levels of control gate material and insulator material;

a vertical string of memory cells formed in the plurality of alternating levels of control gate material and insulator material, the vertical string of memory cells including a semiconductor channel material comprising polysilicon forming a pillar extending vertically through the plurality of alternating levels of control gate material and insulator material, the semiconductor channel material forming a channel for the memory cells of the vertical string of memory cells;

a doped metal silicide common source formed over a substrate and extending between the vertical string of memory cells and the substrate, the doped metal silicide common source in ohmic contact with the polysilicon-comprising semiconductor channel material, wherein dopant from the doped metal silicide common source is diffused into the vertically extending semiconductor channel material, extending upwardly from the doped metal silicide common source;

a capping layer over the doped metal silicide common source, wherein the polysilicon-comprising semiconductor channel material of each vertical string of memory cells extends through a respective opening extending through the plurality of alternating levels of control gate material and insulator material, and through the capping material, to the doped metal silicide common source; and

a material extending between the doped metal silicide common source and the substrate;

wherein memory cells of the vertical string of memory cells are at least partially formed in a respective lateral recess in a level of the control gate material, in which the control gate material is laterally recessed relative to adjacent levels of insulator material, and wherein the memory cells of the vertical string of memory cells comprise:

a dielectric material in the lateral recess adjacent to the control gate material;

a charge storage structure within the lateral recess and adjacent to the dielectric material; and

a tunnel dielectric material between the charge storage structure and the vertically extending, polysilicon-comprising semiconductor channel material.

2. The apparatus of claim 1 , wherein the dielectric material comprises an oxide-nitride-oxide material.

3. The apparatus of claim 1 , wherein the doped metal silicide source comprises an N+ doped metal silicide.

4. The apparatus of claim 3 , wherein the doped metal silicide source is doped with arsenic or phosphorus.

5. The apparatus of claim 1 , further comprising a select gate material and insulator material adjacent to the semiconductor material and between a lowest level of control gate material and the doped metal silicide source.

6. The apparatus of claim 1 , wherein the doped metal silicide source comprises tungsten silicide.

7. The apparatus of claim 1 , wherein the doped metal silicide source comprises a P+ doped metal silicide.

8. The apparatus of claim 7 , wherein the doped metal silicide source is doped with boron or gallium.

9. The apparatus of claim 1 , wherein the semiconductor material further comprises a polysilicon liner adjacent the select gate material, and wherein the polysilicon-containing semiconductor channel material extends within the polysilicon liner.

10. The apparatus of claim 1 , wherein the doped metal silicide source comprises a refractory metal silicide.

11. The apparatus of claim 1 , wherein the refractory metal silicide comprises tantalum silicide or molybdenum silicide.

12. A memory structure, comprising:

a doped metal silicide common source formed over a substrate, a material layer between the doped metal silicide common source and the substrate;

a capping material over the doped metal silicide common source;

multiple vertical strings of memory cells extending above the doped metal silicide common

source, each vertical string of memory cells respectively including,

multiple vertically-arranged charge storage transistors, and

a vertically extending pillar of semiconductor channel material forming a channel of the multiple charge storage transistors in the string;

wherein each of the vertically extending channel materials of respective strings of the multiple strings of memory cells extends upwardly from an ohmic contact with the doped metal silicide common source, and through an opening in the capping material, to the vertically-arranged charge storage transistors of the respective string, wherein the pillar is in selective communication with a respective bit line, and

wherein a dopant of the doped metal silicide common source is diffused into the vertically extending channel materials of each of the multiple vertical strings.

13. The memory structure of claim 12 , wherein the doped metal silicide source comprises a refractory metal silicide.

14. The memory structure of claim 13 , wherein the refractory metal silicide at least one of tungsten silicide, tantalum silicide, or know what molybdenum silicide.

15. The memory structure of claim 12 , wherein the doped metal silicide contains a N+ dopant.

16. A memory structure, comprising:

an N+ doped refractory metal silicide common source over a substrate;

a polysilicon or oxide material separating the N+ doped refractory metal silicide common source and the substrate;

multiple vertical strings of memory cells extending above the N+ doped refractory metal silicide common source, each string of the multiple vertical strings including, multiple vertically-arranged charge storage transistors, each charge storage transistor having a respective control gate,

a respective vertically-extending pillar comprising polysilicon forming a channel for the charge storage transistors of the string, and

tunnel dielectric material between the vertically-extending channel material and each charge storage transistor of the vertical string; and

wherein the vertically extending polysilicon pillar of each of the channels of the respective multiple vertical strings extends vertically from an ohmic contact with the N+ doped refractory metal silicide common source upwardly and adjacent the multiple vertically-arranged charge storage transistors of the respective string; and

wherein N+ dopant from the N+ doped refractory metal silicide common source is diffused into the polysilicon of the vertically extending channel material as a result of the ohmic contact.

Assignments (4)
RELEASE OF SECURITY INTEREST Recorded Nov 12, 2019
From: JPMORGAN CHASE BANK, N.A., AS COLLATERAL AGENT
To: MICRON TECHNOLOGY, INC.; MICRON SEMICONDUCTOR PRODUCTS, INC.
Reel/Frame 051028/0001 →
RELEASE OF SECURITY INTEREST Recorded Oct 9, 2019
From: MORGAN STANLEY SENIOR FUNDING, INC., AS COLLATERAL AGENT
To: MICRON TECHNOLOGY, INC.
Reel/Frame 050680/0268 →
SECURITY INTEREST Recorded Jul 13, 2018
From: MICRON TECHNOLOGY, INC.; MICRON SEMICONDUCTOR PRODUCTS, INC.
To: JPMORGAN CHASE BANK, N.A., AS COLLATERAL AGENT
Reel/Frame 047540/0001 →
SUPPLEMENT NO. 2 TO PATENT SECURITY AGREEMENT Recorded Feb 10, 2017
From: MICRON TECHNOLOGY, INC.
To: MORGAN STANLEY SENIOR FUNDING, INC.
Reel/Frame 041671/0902 →
Continuity (2)
Division 14069553 · Nov 1, 2013
Related Publication 20160372479A1 · Dec 22, 2016