VHF SiH4/H2 plasma characteristics with negative ions

A VHF SiH4/H2 plasma was produced using a multi rod electrode and the plasma parameters were measured using a heated Langmuir probe, where the frequency of the power source was 80 MHz. The Langmuir probe characteristics indicated that when the concentration of SiH4/H2 is increased, negative ions appear and at the same time the electron temperature increases.

► VHF SiH4/H2 plasma was produced using a multi rod electrode of 422 mm × 422 mm. ► The sheath potential was lower than the calculated one for SiH4/H2 of 30%. ► The electron temperature increased to (4–4.5) eV for SiH4/H2 of 30%. ► The probe characteristics indicated the existence of negative ions for 30%.