Temperature Dependence of the Ion Energy Distribution in a Hydrogen Diluted Silane VHF Plasma

Using an energy resolved mass spectrometer we measured the ion energy and abundance of SinH2n+1+(n = 1…5) ions reaching the growing surface as a function of temperature and pressure in a very high frequency (VHF) hydrogen diluted silane plasma. We observed an increase in ion energy with increasing substrate temperature for all species. For low mass ions, we observe an increase in the number of ions reaching the growing surface with increasing temperature, whereas the count rate for high mass ions decreases with increasing temperature. This result confirms the hypothesis that a higher substrate temperature will prevent the plasma from going into the dusty γ′‐regime by suppressing the polymerization reactions of silyl into larger polysilanes which are the precursors for the dust formation.