Constricted Plasma Source

IB-1124

E.O. Lawrence Berkeley National Laboratory

APPLICATION OF TECHNOLOGY:

• Growth of GaN thin films as well as optical films, on glass and plastics
• CD players, flat panel displays, and traffic signals
• Electrochromic coatings for windows
• Creating water-vapor plasmas for better ion-conducting hydrated films
• Implanting nitrogen ions in lithium with ultimate aim of making recyclable lithium batteries

ADVANTAGES:

• Rugged and low-cost
• Can operate at either low or high pressures
• Produces low-temperature plasmas with high percentages of the desired species of ionized gas
• Permits the formation of delicate crystalline films impossible to make using other kinds of plasma sources

ABSTRACT:

The constricted plasma source (CPS), a new, rugged, low-cost device, was developed by Simone Anders, Andre Anders, Michael Dickinson, Mike Rubin and colleagues at Berkeley Lab for growth of GaN thin films, as well as optical films, on glass and plastics. This 1997 R&D 100 Award-winning technology utilizes a constricted glow discharge, characterized by the presence of a small orifice (or constriction) placed in the discharge path between cathode and anode. Ionization processes occur in the vicinity of the constriction, and the ionized gas (plasma) is "blown" through the constriction by the pressure gradient. Existing plasma sources operate at low pressures and high energies. By contrast, the CPS can operate at either low or high pressures, producing low-temperature plasmas with high percentages of the desired species of ionized gas. Low ion energies permit the formation of delicate crystalline films impossible to make using other kinds of plasma sources. With nitrogen, the CPS can help create blue LEDs and laser diodes, useful in CD players, flat panel displays, and traffic signals. With oxygen, it can assist in the deposition of a variety of oxide films including promising electrochromic coatings for windows. Other possible applications include creating water-vapor plasmas for better ion-conducting hydrated films or implanting nitrogen ions in lithium, with the ultimate aim of making recyclable lithium batteries, a potential boon to the electric car market.

STATUS:

• U.S. Patents #6,137,231, #6,140,773, #6,388,381
• Available for licensing

REFERENCE NUMBER: IB-1124