Measurements of electron density in helicon-wave excited high-density reactive plasmas by vacuum ultraviolet emission spectroscopy

This paper reports vacuum ultraviolet (VUV) emission spectroscopy for non-contact measurements of the electron density in reactive plasmas. The advantages of the VUV emission spectroscopy compared with the visible one are (1) the applicability to high-density plasmas close to 10(14) cm(-3) and (2) the insensitivity against the variation of the velocity distribution function of electrons. in this paper, the VUV emission spectroscopy is adapted to helicon-wave excited high-density fluorocarbon plasmas. As a result, a reasonable agreement has been obtained between the result of the present method and the electron density measured by a microwave interferometer. The accuracy of the present method is discussed in detail considering several sources of error.