Memory device and method of reading data

Patent metadata

Field	Value
Publication number	US-2020098433-A1
Application number	US-201916434968-A
Country	US
Kind code	A1
Filing date	Jun 7, 2019
Priority date	Sep 20, 2018
Publication date	Mar 26, 2020
Grant date	—

Abstract

A non-volatile memory includes a memory cell region including an outer region proximate a first end of the memory cell region and an inner region separated from the first end by the outer region, first and second bit lines, an outer memory cell string including memory cells connected to an outer pillar extending vertically upward through the outer region, and an inner memory cell string including memory cells connected to an inner pillar extending vertically upward through the inner region, and a data input/output (I/O). The data I/O circuit includes a page buffer circuit that connects the first bit line during a first read operation directed to memory cells of the outer memory cell string, and connects the second bit line during a second read operation directed to memory cells of the inner memory cell string, and a read voltage determination unit that selects a first optimal read voltage used during the first read operation, and a second optimal read voltage used during the second read operation.

First claim

1 . A non-volatile memory, comprising:
a memory cell region including an outer region proximate a first end of the memory cell region and an inner region separated from the first end by the outer region; first and second bit lines; an outer memory cell string including memory cells connected to an outer pillar extending vertically upward through the outer region, and an inner memory cell string including memory cells connected to an inner pillar extending vertically upward through the inner region; and a data input/output (I/O) circuit including:
a page buffer circuit that connects the first bit line during a first read operation directed to memory cells of the outer memory cell string, and connects the second bit line during a second read operation directed to memory cells of the inner memory cell string, and
a read voltage determination unit that selects a first optimal read voltage used during the first read operation, and a second optimal read voltage used during the second read operation.

2 . The non-volatile memory of claim 1 , wherein the first bit line and second bit line are paired bit lines extending over an upper surface of the memory cell array.

3 . The non-volatile memory of claim 2 , wherein page buffer circuit includes a first page buffer that connects to the first bit line during the first read operation, and a second page buffer that connects to the second bit line during the second read operation.

4 . The non-volatile memory of claim 1 , wherein the memory cell region further includes a vertically-stacked plurality of word lines extending in a first horizontal direction, and
the first and second bit lines extend in a second horizontal direction.

5 . The non-volatile memory of claim 1 , further comprising control logic that controls the data I/O circuit to perform the first read operation independent from the second read operation.

6 . The non-volatile memory of claim 5 , wherein the control logic controls the data I/O circuit to simultaneously perform the first read operation and the second read operation.

7 . The non-volatile memory of claim 1 , wherein the outer memory cell string is one of a plurality of outer memory cell strings, each outer memory cell string including memory cells connected to a corresponding outer pillar extending vertically upward through the outer region, and the inner memory cell string is one of a plurality of inner memory cell strings, each inner memory cell string including memory cells connected to a corresponding inner pillar extending vertically upward through the inner region,
a center of each outer pillar is disposed at least a first distance from the first end and a center of each inner pillar is disposed at least a second distance from the first end, and the second distance being greater than the first distance.

8 . The non-volatile memory of claim 7 , wherein
the corresponding outer pillars are collectively arranged in a first pillar row extending in a first horizontal direction, the corresponding inner pillars are collectively arranged in a second pillar row extending in the first horizontal direction, the first pillar row and the second pillar row are disposed in a staggered-row arrangement, and the first and second bit lines extend in a second horizontal direction.

9 . The non-volatile memory of claim 1 , wherein the non-volatile memory is a vertical NAND flash memory, the outer memory cell string is a first NAND string connected between the first bit line and a common source line (CSL), and the inner memory cell string is a second NAND string connected between the second bit line and the CSL.

10 . The non-volatile memory of claim 9 , wherein the first NAND string has a first connection resistance between the first bit line and the CSL, and the second NAND string has a second connection resistance between the second bit line and the CSL, different from the first connection resistance.

11 . A non-volatile memory, comprising:
a memory cell region including a first end, an outer region proximate the first end and an inner region separated from the first end by the outer region; first and second bit lines; an outer memory cell string including memory cells connected to an outer pillar extending vertically upward through the outer region, and an inner memory cell string including memory cells connected to an inner pillar extending vertically upward through the inner region; and a data input/output (I/O) circuit including:
a page buffer circuit including a first page buffer that connects the first bit line during a first read operation directed to memory cells of the outer memory cell string, and a second page buffer that connects the second bit line during a second read operation directed to memory cells of the inner memory cell string, and
a read voltage determination unit that selects a first optimal read voltage used during the first read operation, and a second optimal read voltage, different from the first optimal read voltage, used during the second read operation,
wherein the first page buffer includes a first storing register that stores a first candidate read voltage and a second storing register that store a second candidate read voltage, and the read voltage determination unit selects one of the first candidate read voltage and the second candidate read voltage as the first optimal read voltage.

12 . The non-volatile memory of claim 11 , wherein the first page buffer further includes:
a bit line shut-off transistor connecting the first bit line with a sensing node; a sensing register that senses voltage on the first bit line during the first read operation; an output register that stores first output data resulting from the first read operation, wherein the sensing register, first storing register, second storing register and output register are respectively connected to the sensing node.

13 . The non-volatile memory of claim 11 , wherein the second page buffer includes a first storing register that stores a first candidate read voltage and a second storing register that store a second candidate read voltage, and
the read voltage determination unit selects one of the first candidate read voltage and the second candidate read voltage as the second optimal read voltage.

14 . The non-volatile memory of claim 13 , wherein the second page buffer further includes:
a bit line shut-off transistor connecting the second bit line with a sensing node; a sensing register that senses voltage on the second bit line during the second read operation; an output register that stores second output data resulting from the second read operation, wherein the sensing register, first storing register, second storing register and output register are each respectively connected to the sensing node.

15 . The non-volatile memory of claim 13 , wherein at least one of the first candidate read voltage stored in the first storing register of the first page buffer and the second candidate read voltage stored in the second storing register of the first page buffer is the same as at least one of the first candidate read voltage stored in the first storing register of the second page buffer and the second candidate read voltage stored in the second storing register of the second page buffer.

16 . The non-volatile memory of claim 11 , wherein the outer memory cell string is one of a plurality of outer memory cell strings, each outer memory cell string including memory cells connected to a corresponding outer pillar extending vertically upward through the outer region, and the inner memory cell string is one of a plur

Assignees

• Samsung Electronics Co Ltd

Inventors

• Jeon Su Chang
• Kim Seung Bum
• Lee Ji Young

Classifications

• G11C16/26

  Sensing or reading circuits; Data output circuits · CPC title

• G11C16/24 Primary

  Bit-line control circuits · CPC title

• G11C16/0483

  comprising cells having several storage transistors connected in series · CPC title

• G11C2207/002

  Isolation gates, i.e. gates coupling bit lines to the sense amplifier · CPC title

• G11C16/32

  Timing circuits · CPC title