Large Area SiH4/H2 VHF Plasma Produced with Multi-Rod Electrode

Abstract

A SiH4/H2 VHF plasma with a frequency of 60 MHz was produced with a multi-rod electrode of 1 200 × 114 mm2 at high pressure. The plasma parameters were measured as a function of pressure and concentration of SiH4 to H2 with a tiny heated Langmuir probe. When the pressure was increased, the plasma density decreased independent of the concentration of SiH4 to H2, while the electron temperature increased to about 11 eV at 3 Torr. The wall potential defined as the potential difference between the plasma potential and the floating potential was anomalously small at high pressure, suggesting very low ion bombardment. Furthermore, Langmuir probe characteristics indicated that there exist much negative ions.