Read with look-back combined with programming with asymmetric boosting in memory
US9349478B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 29, 2014 |
| Grant date | May 24, 2016 |
| Priority date | — |
| Expiry date | Jan 27, 2035 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C29/52
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A read operation compensates for program disturb when distinguishing between an erased-state and a lowest programmed data state, where the program disturb is a function of the data state of an adjacent, previously-programmed memory cell on a common charge-trapping layer. A programming operation avoids program disturb of the programmed data states by using asymmetric pass voltages. Before reading the memory cells on a selected word line (WLn), the memory cells on the adjacent, previously-programmed word line (WLn−1) are read. The read operation for WLn uses multiple read voltages—one for each data state on WLn−1, and one of the read results is selected based on the data state of the adjacent memory cell. Other read operations distinguish between each pair of adjacent programmed data states using a read voltage which is independent of the data state of the adjacent memory cell.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.