Bulb-shaped memory stack structures for direct source contact in three-dimensional memory device
US10008570B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 14, 2017 |
| Grant date | Jun 26, 2018 |
| Priority date | — |
| Expiry date | Mar 14, 2037 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10B43/40
Abstract
The contact area between a source strap structure of a buried source layer and semiconductor channels within memory structures can be increased by laterally expanding a source-level volume in which the memory stack structures are formed. In one embodiment, sacrificial semiconductor pedestals can be formed in source-level memory openings prior to formation of a vertically alternating stack of insulating layers and sacrificial material layers. Memory openings can include bulging portions formed by removal of the sacrificial semiconductor pedestals. Memory stack structures can be formed with a greater sidewall surface area in the bulging portions to provide a greater contact area with the source strap structure. Alternatively, bottom portions of memory openings can be expanded selective to upper portions during, or after, formation of the memory openings to provide bulging portions and to increase the contact area with the source strap structure.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.