公开(公告)号：US11501831B2

公开(公告)日：2022-11-15

申请号：US17090438

申请日：2020-11-05

Applicant: SanDisk Technologies LLC

Inventor： Neil Robertson ,  Michael Grobis ,  Ward Parkinson

IPC: G11C11/00 ,  G11C13/00

Abstract: In a memory array with a cross-point structure, at each cross-point junction a programmable resistive memory element, such as an MRAM memory cell, is connected in series with a threshold switching selector, such as an ovonic threshold switch. The threshold switching selector switches to a conducting state when a voltage above a threshold voltage is applied. When powered down for extended periods, the threshold voltage can drift upward. If the drift is excessive, this can make the memory cell difficult to access and can disturb stored data values when accessed. Techniques are presented to determine whether excessive voltage threshold drift may have occurred, including a read based test and a time based test.

公开(公告)号：US10134457B1

公开(公告)日：2018-11-20

申请号：US15692920

申请日：2017-08-31

Applicant: SanDisk Technologies LLC

Inventor： Goran Mihajlovic ,  Jordan Katine ,  Neil Robertson ,  Neil Smith

IPC: G11C11/00 ,  G11C11/16 ,  H01L27/22

Abstract: Apparatuses, systems, and methods are disclosed for magnetoresistive random access memory. A plurality of read lines are in a read line layer, and a plurality of write lines are in a write line layer. A plurality of spin accumulation lines are in a spin accumulation line layer disposed between a read line layer and a write line layer. Spin accumulation lines may horizontally cross read lines and write lines. A plurality of vertical magnetoresistive random access memory (MRAM) cells may include polarizers and magnetic tunnel junctions. A vertical MRAM cell may include a polarizer coupled between a spin accumulation line and a write line. A vertical MRAM cell may further include a magnetic tunnel junction coupled between a spin accumulation line and a read line, such that the magnetic tunnel junction and the polarizer are vertically aligned.

公开(公告)号：US20230005539A1

公开(公告)日：2023-01-05

申请号：US17943550

申请日：2022-09-13

Applicant: SanDisk Technologies LLC

Inventor： Neil Robertson ,  Michael Grobis ,  Ward Parkinson

IPC: G11C13/00

Abstract: In a memory array with a cross-point structure, at each cross-point junction a programmable resistive memory element, such as an MRAM memory cell, is connected in series with a threshold switching selector, such as an ovonic threshold switch. The threshold switching selector switches to a conducting state when a voltage above a threshold voltage is applied. When powered down for extended periods, the threshold voltage can drift upward. If the drift is excessive, this can make the memory cell difficult to access and can disturb stored data values when accessed. Techniques are presented to determine whether excessive voltage threshold drift may have occurred, including a read based test and a time based test.

公开(公告)号：US10354710B2

公开(公告)日：2019-07-16

申请号：US15728840

申请日：2017-10-10

Applicant: SANDISK TECHNOLOGIES LLC

Inventor： Christopher Petti ,  Neil Robertson ,  Abhijit Bandyopadhyay

IPC: G11C11/16 ,  G11C11/02

Abstract: A memory cell includes a VCMA magnetoelectric memory element and a two-terminal selector element connected in series to the magnetoelectric memory element.

公开(公告)号：US11783895B2

公开(公告)日：2023-10-10

申请号：US17943550

申请日：2022-09-13

Applicant: SanDisk Technologies LLC

Inventor： Neil Robertson ,  Michael Grobis ,  Ward Parkinson

IPC: G11C11/00 ,  G11C13/00

CPC classification number: G11C13/0069 ,  G11C13/003 ,  G11C13/004 ,  G11C13/0004 ,  G11C13/0038 ,  G11C13/0061

Abstract: In a memory array with a cross-point structure, at each cross-point junction a programmable resistive memory element, such as an MRAM memory cell, is connected in series with a threshold switching selector, such as an ovonic threshold switch. The threshold switching selector switches to a conducting state when a voltage above a threshold voltage is applied. When powered down for extended periods, the threshold voltage can drift upward. If the drift is excessive, this can make the memory cell difficult to access and can disturb stored data values when accessed. Techniques are presented to determine whether excessive voltage threshold drift may have occurred, including a read based test and a time based test.

公开(公告)号：US20220139454A1

公开(公告)日：2022-05-05

申请号：US17090438

申请日：2020-11-05

Applicant: SanDisk Technologies LLC

Inventor： Neil Robertson ,  Michael Grobis ,  Ward Parkinson

IPC: G11C13/00

Abstract: In a memory array with a cross-point structure, at each cross-point junction a programmable resistive memory element, such as an MRAM memory cell, is connected in series with a threshold switching selector, such as an ovonic threshold switch. The threshold switching selector switches to a conducting state when a voltage above a threshold voltage is applied. When powered down for extended periods, the threshold voltage can drift upward. If the drift is excessive, this can make the memory cell difficult to access and can disturb stored data values when accessed. Techniques are presented to determine whether excessive voltage threshold drift may have occurred, including a read based test and a time based test.