Non-volatile semiconductor storage apparatus and production thereof
US5891773A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 23, 1997 |
| Grant date | Apr 6, 1999 |
| Priority date | — |
| Expiry date | Jul 23, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10B41/30
Abstract
The invention provides a non-volatile semiconductor storage apparatus wherein silicon pillars are formed by epitaxial growth thereby to suppress a dispersion in channel length and improve the quality of a gate oxide film. In production, epitaxial silicon pillars are formed by selective epitaxial growth on a p-type silicon substrate, and a gate oxide film is formed over the overall area. Polycrystalline silicon is deposited and etched back to form a first polycrystalline silicon film serving as floating gates. Ion implantation is performed to form drain regions at the tops of the epitaxial silicon pillars and form a source region on the surface of the silicon substrate. A layered insulation film is formed, and polycrystalline silicon is deposited and etched back to form a second polycrystalline silicon film which covers over the side faces of the floating gates and serves as control gates. Bit lines are formed on the drain regions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.