Three-dimensional semiconductor memory devices and methods of operating the same
US10971238B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 16, 2019 |
| Grant date | Apr 6, 2021 |
| Priority date | — |
| Expiry date | Dec 16, 2039 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C16/26
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Three-dimensional semiconductor memory devices are provided. A three-dimensional semiconductor memory device includes a plurality of word line blocks including a plurality of cell strings that are connected in parallel between a bit line and a common source line. Each of the cell strings includes a plurality of memory cell transistors that are stacked on a substrate in a vertical direction, a plurality of ground selection transistors that are connected in series between the plurality of memory cell transistors and the substrate, and a string selection transistor that is between the plurality of memory cell transistors and the bit line. In each of the cell strings, at least one of the plurality of ground selection transistors has a first threshold voltage, and remaining ones of the ground selection transistors have a second threshold voltage different from the first threshold voltage. Related methods of operating three-dimensional semiconductor memory devices are also provided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.