High-density IC isolation technique capacitors
US4512816A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 23, 1984 |
| Grant date | Apr 23, 1985 |
| Priority date | — |
| Expiry date | Apr 23, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/761
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A semiconductor substrate having an epitaxial layer on its upper surface is provided with a masking layer. Holes are photolithographically etched in the masking layer where isolation diffusion regions are to be formed. Then aluminum ions are implanted into the surface and diffused completely through the epitaxial layer so as to create tubs of epitaxial material that are PN junction isolated. Since aluminum is a fast diffuser, the diffusion time is greatly reduced, thereby reducing the up diffusion of buried N+ collector so that the original epitaxial layer can be made relatively thin. Lateral isolation diffusion is reduced, thereby substantially reducing the surface area required for isolation. Thus, the process is capable of increasing the component density in the completed integrated circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.