First fire and cold start in memories with threshold switching selectors
US11894037B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 12, 2022 |
| Grant date | Feb 6, 2024 |
| Priority date | — |
| Expiry date | Aug 31, 2042 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/1443
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
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. Techniques are also presented for initializing a cross-point array, for both first fire and cold start, by using voltage levels shifted from half-select voltage levels used in a standard memory access.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.