Semiconductor memory device including a floating gate having an undoped edge portion proximate to a source portion of the memory device
US5446298A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 6, 1994 |
| Grant date | Aug 29, 1995 |
| Priority date | — |
| Expiry date | Sep 6, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D30/685
Abstract
The present invention provides a semiconductor device including nonvolatile memories and a manufacturing method thereof which have advantages in reliability of writing operation and in erasing time of erasing operation. This semiconductor device comprises a silicon substrate 40, a N type drain 40 formed in the surface of the substrate 36, a N type source 36, a tunnel oxide layer 14 located on the surface of the substrate, and a floating gate located on the tunnel oxide layer 14, having a first portion 55 in side of the source 36 and a second portion 54 in both sides of the drain 40 and the substrate 2, the second portion 54 being of a lower N type dosage than the first portion 55.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.