In this work we show that it is possible to control the plasma regime in the region close to the substrate in r.f. silane discharges. The PECVD reactor works in a modified triode configuration, where the control over the plasma regime is performed by polarising a grid electrode, placed close to the r.f. electrode, with a DC power source. Besides that, the DC grid allows also to control the energy of the ion bombardment, because the plasma potential will be a function of the voltage (Vpol) applied to the DC grid. The silane plasma was characterised with a Langmuir probe and an impedance probe. We were able to identify three plasma regimes in the region close to the substrate: γ′ regime for Vpolpolpol40 V. The γ′ regime is associated with a high concentration of dust particles in plasma and high electron energy (≈8eV), while the α regime is associated with a free dust plasma and low electron energy (≈2eV). The intermediate regime, γ′-α, is characterised by the presence of smaller particles (≈2-5nm) that can be beneficial for the film's properties.

Original languageEnglish
Pages (from-to)387-392
Number of pages6
Issue number3-4
Publication statusPublished - Jan 2002


  • Amorphous silicon
  • Dusty plasmas
  • Langmuir probe

Fingerprint Dive into the research topics of 'Influence of a DC grid on silane r.f. plasma properties'. Together they form a unique fingerprint.

Cite this