Feasibility study of a new negative ion source using a transformer coupled plasma source

Abstract

Multicusp volume ion sources with radio frequency (rf) antenna are well accepted negative ion sources except for the contamination problem from the rf antenna immersed in the plasma. The transformer coupled plasma (TCP) developed as high-density plasma sources for processing of microelectronics is newly recognized as a good candidate for negative ion sources without this contamination problem. High-density plasmas can be generated with the rf antenna outside of the plasma chamber separated by a dielectric window. Also, this high-density, high-temperature, heating region can be well separated from the negative ion extraction region where low electron temperatures are required. Moreover, TCP does not require a magnetic field for plasma generations; electron filtering with transverse magnetic field is compatible. Feasibility of the TCP negative ion source has been confirmed with plasma characteristics. Conceptual design of a new novel ion source based on the TCP source is performed.