Abstract
The effect of excitation frequency in processing plasmas of the very-high-frequency band has been studied by plasma diagnostics including Langmuir probe and optical emission spectroscopy. The ECR plasma has been implemented in the VHF (144 MHz) range. Properties of hydrogenated amorphous silicon films have also been studied. High-quality interfaces have been demonstrated through the characteristics of thin-film transistors prepared by VHF plasma CVD.