Double verify method with soft programming to suppress read noise
US8902668B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 15, 2013 |
| Grant date | Dec 2, 2014 |
| Priority date | — |
| Expiry date | Oct 15, 2033 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C16/3454
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Memory cells which have read noise are identified during a programming pass and an amount of programming is increased for noisy memory cells compared to non-noisy cells. The read noise is indicated by a decrease in the threshold voltage of a cell when the cell is repeatedly read. During the programming pass, a cell enters a temporary lockout state when it passes a first verify test. In this state, the cell is subject to one or more additional verify tests. If the one or more additional verify tests indicate that the threshold voltage of a cell has decreased, the cell is noisy and is soft programmed before being permanently locked out. In contrast, programming of a non-noisy cell is concluded after the first verify test without further programming.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.