Indirectly heated button cathode for an ion source
US6878946B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 30, 2002 |
| Grant date | Apr 12, 2005 |
| Priority date | — |
| Expiry date | Sep 30, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/082
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An indirectly heated button cathode for use in the ion source of an ion implanter has a button member formed of a slug piece mounted in a collar piece. The slug piece is thermally insulated from the collar piece to enable it to operate at a higher temperature so that electron emission is enhanced and concentrated over the surface of the slug piece. The slug piece and collar piece can be both of tungsten. Instead the slug piece may be of tantalum to provide a lower thermionic work function. The resultant concentrated plasma in the ion source is effective to enhance the production of higher charge state ions, particularly P+++ for subsequent acceleration for high energy implantation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.