Particle formation in RF silane plasmas

In this work we present experimental results obtained using the microwave resonance technique for electron density measurements combined with electrical characterisation of a low pressure rf discharge. Electron density measurements in a SiH4/He/Ar mixture showed that the electron density experiences a peak at around 300 µs after the plasma ignition with a characteristic rise time of 80 µs, followed by a rapid decrease with a characteristic time of 0.66 ms. This decrease is not observed in pure argon and should most probably be attributed to the formation of negative ions and particles in the silane plasma