Method of improving uniformity of metal-to-poly capacitors composed by polysilicon oxide and avoiding device damage
US5658821A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 27, 1996 |
| Grant date | Aug 19, 1997 |
| Priority date | — |
| Expiry date | Sep 27, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/32105
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method of forming capacitors comprising polysilicon, polysilicon oxide, metal is described which significantly improves uniformity of capacitance across the silicon integrated circuit wafer and avoids damage to electrical contact regions. A first layer of polysilicon oxide is formed on a polysilicon first capacitor plate. The wafer is then dipped in a buffered oxide etch or subjected to a dry anisotropic etch. The etching conditions the polysilicon layer so that subsequent polysilicon oxide growth is very uniform and controllable. A second polysilicon oxide layer is then formed on the polysilicon first capacitor plate. A layer of silicon nitride is formed on the polysilicon oxide and a second capacitor plate is formed on the layer of silicon nitride completing the capacitor. Improved capacitance uniformity across the wafer is achieved and device damage is avoided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.