Programmable read-only memory
US4933736A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 10, 1989 |
| Grant date | Jun 12, 1990 |
| Priority date | — |
| Expiry date | Mar 10, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10B20/25
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A semiconductor PROM contains a group of PROM cells (12) each consisting of a pair of opposing diodes oriented vertically with their common intermediate region (22) fully adjoining a recessed oxide insulating region (16). A composite buried layer consisting of buried regions (32) which adjoin the insulating region below the lower cell regions (20) and an opposite-conductivity buried web (44) which laterally surrounds each buried region is employed to improve programming efficiency. Connective regions (46) extend from the buried web to the upper semiconductor surface to contact electrical leads (54) typically arranged in a parallel pattern. The maximum dopant concentration in the intermediate cell regions occurs vertically within 20% of their mid-points.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.