System and method for increasing breakdown voltage of LOCOS isolated devices
US7867871B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 13, 2006 |
| Grant date | Jan 11, 2011 |
| Priority date | — |
| Expiry date | Jul 13, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/76205
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
An efficient method is disclosed for increasing the breakdown voltage of an integrated circuit device that is isolated by a local oxidation of silicon (LOCOS) process. The method comprises forming a portion of a field oxide in an integrated circuit so that the field oxide has a gradual profile. The gradual profile of the field oxide reduces impact ionization in the field oxide by creating a reduced value of electric field for a given value of applied voltage. The reduction in impact ionization increases the breakdown voltage of the integrated circuit. The gradual profile is formed by using an increased thickness of pad oxide and a reduced thickness of silicon nitride during a field oxide oxidation process.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.