Characteristics of the electron temperature in VHF-excited SiH4/H2 plasma produced using a ladder-shaped electrode

Discharge frequency was selected at 80MHz to generate VHF-excited SiH4/H2 plasma using a ladder-shaped electrode. The plasma parameters were measured using a heated Langmuir probe. The effect of hydrogen dilution on SiH4/H2 VHF plasma characteristics was investigated. The electron temperature took the minimum value at SiH4 flow rate/(SiH4 flow rate + H2 flow rate)=4–9%, which is corresponding to the H2 dilution rate near the deposition condition of hydrogenated microcrystalline silicon films. The rate of H2 dilution where electron temperature takes the minimum value depended on RF power.