THE EFFECTS OF A SMALL TRANSVERSE MAGNETIC-FIELD UPON A CAPACITIVELY COUPLED RF DISCHARGE

A capacitively-coupled RF argon discharge at a pressure of 10 mTorr wi th a plate separation of 7.5 cm has been studied both experimentally a nd using a one-dimensional particle in cell simulation with Monte Carl o collisions. A magnetic held of 0 to 60 G is applied in the direction parallel to the capacitor plates. In the simulation it was found that as the magnetic held was increased such that the electron cyclotron o rbit radius of the hot electrons became smaller than of the order of t he discharge length, the electron heating in the bulk of the discharge increased. The dominant electron. heating mechanism was observed to c hange from a stochastic sheath to a bulk ohmic electron heating mode, with a variation of field from 0 to 10 G. This was accompanied by a dr op in the plasma density at small magnetic fields, which was also obse rved experimentally. At higher magnetic fields the plasma density was found to increase. A detailed discussion of the simulation results is presented drawing comparisons with the experimental results, with whic h there is good agreement, and a simple magnetohydrodynamic model for the bulk heating.