Electron cyclotron resonance sources for wide and narrow plasma streams

Abstract

Characteristics, performance, and design features of 3- and 6-in. diam electron cyclotron resonance plasma stream sources are presented. Three types of plasma streams were found and studied: (1) uniform with low-level microwave power absorption and low plasma density, (2) nonuniform narrow column or ring with high-level microwave power absorption and plasma density, and (3) large-area (wide) uniform stream with moderate plasma density. It was found that the highest plasma densities in streams were reached when the magnetic field near the vacuum window was 875 and 935 G. With microwave power of 800–1000 W and gas pressures of 2–6×10−4 Torr (argon, nitrogen, oxygen), both 3- and 6-in. sources can deliver at distance of 30 cm uniform streams with plasma densities of 4–6×1010 cm−3 and uniformity of ±5% over an area larger than 15 cm in diameter.