Method and apparatus for coupling a microwave source in an electron cyclotron resonance system
US5111111A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 27, 1990 |
| Grant date | May 5, 1992 |
| Priority date | — |
| Expiry date | Sep 27, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05H7/02
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A microwave source is coupled to an electron cyclotron resonance (ECR) system by circularly polarizing the microwave energy from the source in an angular direction with cooperates with the ECR system's magnetic field to produce electron cyclotron resonance, and coupling the circularly polarized microwave energy to the plasma using a quarter wave vacuum window transformer having a dielectric constant which matches the impedance of the circularly polarized microwave energy to the impedance of the plasma. The impedance matching transformer is preferably a vacuum window of the ECR chamber having quarter wave thickness and the appropriate dielectric constant. For high density plasmas in a standard ECR system of 6 cm radius an alumina window 0.98 cm thick procides optimum coupling. The reflected power from the plasma is thereby minimized to provide a dense plasma for the ECR tool while reducing or eliminating the need for manual external tuners for the microwave source.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.