Characteristics of VHF-excited SiH4 plasmas using a ladder-shaped electrode

A very high frequency (VHF) excited SiH4 plasma is produced with a ladder-shaped electrode and the SiH4 plasma parameters are measured with a heated Langmuir probe. When the discharge frequency (∼100 MHz) of the RF power source is increased, the plasma density increases while the electron temperature decreases. Negative ions exist in the SiH4 plasma and the relative density of the negative ion increases with increases in the discharge frequency.