Nonvolatile semiconductor storage device and method of manufacturing
US5793081A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 5, 1997 |
| Grant date | Aug 11, 1998 |
| Priority date | — |
| Expiry date | May 5, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10B69/00
Abstract
A nonvolatile semiconductor storage device in which a composite gate of a floating gate memory cell transistor and a gate electrode of a peripheral MOS transistor are formed in the same lithography process and a manufacturing method thereof. A polycrystalline silicon film and an ONO film are formed on a well region through a gate oxide film and a tunnel oxide film. A polycrystalline silicon film is formed after removing the ONO film in the right region. A floating gate and a control gate of the memory cell transistor and a gate electrode of the select transistor are formed with photoresist as a mask. Thereafter, ions of impurities are implanted and diffused in a transverse direction, thereby to form an impurity diffused layer. With this, since the impurity diffused layer is formed by transverse diffusion of impurities after the tunnel oxide film is formed, it is possible to prevent deterioration of the film quality of the tunnel oxide film.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.