Porcelain-Coated RF Antenna

IB-918

E.O. Lawrence Berkeley National Laboratory

APPLICATIONS OF TECHNOLOGY:

• Ion Implantation: Hardening of materials such as automotive parts or medical tools, semiconductor pacification, plasma processing.
• High Energy Accelerators: Mass spectrometer cyclotrinos, medical proton therapy, neutral, positive or negative beam applications, fusion.
• Neutron Tubes: Wellbore logging applications.
• Waste minimization: Chemical and radioactive waste treatment.

ADVANTAGES:

• RF source better than filament or other conventional plasma generators. RF power coupling produces cleaner plasmas and ion implants. RF power sources available commercially and easily controlled. No need for expensive electronics.
• Twice as efficient as uncoated RF sources, since it is electrically non-conductive.
• Water-cooled. Longer life times. Avoids radiative heat problems. Also protects RF source power source and seal.
• Even implant of ions on irregularly-shaped objects. Opens the door to plasma processing of complex objects impossible before now such as engine blocks.
• Clean operating. Will not sputter. Does not contaminate plasma. Result: purer ion implants.
• Works with a wide variety of gases, including O2 and corrosive BF3.
• Narrow implant profile, important in oxygen implant applications.
• Works both in pulsed and continuous modes.
• Non-reactive. Will last at least ten times as long as filament sources. Makes all applications much more cost-effective.
• Sturdy. Can withstand physical shock, transport, and space launch.
• Porcelain coating technique works on antennas from centimeters to a meter in diameter.
• Demonstrated RF power coupling > 25kW (cw) and > 50kW (pulsed)

ABSTRACT: Long-lasting, versatile RF antenna for clean plasma generation. Ka-Ngo Leung and colleagues at Berkeley National Laboratory have designed a porcelain-coated antenna improves ion and plasma sources used to generate positive, negative or neutral particle beams. Used for ion implantation it allows the processing of large, irregularly-shaped objects, such as whole engine blocks, difficult or impossible to do before now. It works with corrosive gases, has a much longer life time than conventional sources, and does not require expensive electronics. It does not suffer from sputtering, assuring cleaner plasmas and purer ion implants.

The RF antenna has excellent thermal coupling between its hard porcelain enamel coating and water-cooled metal-tube substrate, allowing it to operate at high temperatures for longer periods of time. Since the antenna is cooled it will not cause radiative heating problems in ion implant applications. This cooling also protects the antenna chamber mount. The hard coating prevents unwanted sputtering, ensuring a life span at least ten times as long as standard ion sources. Its non-reactive properties also make it ideal for ion implantation applications with corrosive gases and for continuous operation applications. Due to its sturdy construction it can survive mechanical impacts, heat stress and a hot plasma environment.

STATUS: U.S. Patent #5,587,226. Available for licensing in specific fields of use

REFERENCE NUMBER: IB-918