Study of argon additive in a beam injection type negative ion source using VUV emission spectroscopy

摘要

Effects of Ar addition are studied by using a beam injection type negative ion source. With adding Ar, I_(H~-) increases at low base H_2 pressure. At high base H_2 pressure, however, I_(H~-) decreases. VUV emission intensities also decrease at high base pressure. In other words, Ar addition is adverse effect for production of H_2 (v"). Therefore, decrease in I_(H~-) is caused by decrease in H_2 (v"). In D_2 plasmas, variation patterns of plasma parameters and VUV intensities by Ar addition are nearly the same as ones in H_2 plasmas. Even in low base pressure, however, enhancement of I_(D~-) is not observed.