Inductively coupled plasma (ICP) argon discharge with additional RF bias on the electrode is studied numerically and compared with experimental data. The role of ion inertia is shown by comparing the two numerical approaches: drift-diffusion approximation and a separate equation for ion momentum in the model. Two different discharge geometries are studied: simple cylindrical geometry and two chambers geometry with a downstream plasma. The difference in the calculated plasma density is shown for lower pressure values. Two approaches give similar results at a pressure of 100 mTorr. The downstream ICP discharge with an additional 12 MHz bias was calculated for the range of voltage amplitude from 20 to 215 V. The ion energy distribution function at the RF-biased electrode is calculated by the kinetic model. The results are compared with experimentally measured plasma density and ion energy spectra in the two-chamber discharge geometry. A good agreement was obtained between the calculated and experimental data.

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Numerical and analytical approaches of plasma density determination from the ion current to cylindrical Langmuir probe are validated on hairpin probe measurements. The argon inductively coupled plasma discharge in a pressure range from 4.5 mTorr to 27 mTorr is studied. The discharge input power is varied in the range from 200 to 800 W, giving the plasma density in the range from 10​9 to 10​11 cm​-3. The used approaches for plasma density determination are analytical collisionless OML (orbital-motion-limited) theory, fluid semianalytical model of ion radial motion with ion collisions and Particle-in-Cell with Monte Carlo collisions model of ion current collection by the cylindrical Langmuir probe. Relative error of different models is shown. The ion collisions should be taken into account even at relatively low pressures in order to get a reliable plasma density value from ion current to the Langmuir probe.