Investigation of plasma parameters in a VHF plasma with narrow gap under high gaseous pressure

The plasma parameters in a VHF plasma with a narrow gap under high gaseous pressure were experimentally investigated. As a result of the Langmuir probe measurement for hydrogen plasma with a gap length of 5 mm and a pressure of 1 torr, it was found that the electron temperature (-10 eV) was high enough to promote the dissociation reaction of SiH₄ molecules, and that a large amount of negative ions which could play a role in reducing the sheath potential were produced. On the other hand, the results of the ion measurement using a quadrupole mass spectrometer with an energy analyzer indicated that the highest produced ion was H₃^- and its incident energy to the substrate was low due to the collisions. These results suggest that the condition of high pressure and narrow gap are advantageous for the preparation of high-quality μc-Si thin films