Magnetic field induced mode transition in capacitive CF₄ plasmas

External magnetic fields offer greater flexibility in controlling process-relevant parameters in capacitively coupled plasmas, while also introducing additional complexity to the discharge. The effects of a transversal magnetic field on the electron power absorption dynamics in capacitive CF₄ plasmas are studied based on Particle-in-cell/Monte Carlo Collision simulations. A magnetic field induced electropositive core, characterized by a pronounced electron density peak within the otherwise strongly electronegative plasma bulk region, is identified and the corresponding mode of discharge operation is referred to as the magnetized drift-ambipolar mode [1]. The magnetic field is also found to elevate ion densities beyond the threshold required for the formation of striations, thereby inducing a drift-ambipolar to striation mode transition, while under high pressures the striation mode is disrupted by the magnetic field due to the development of an electropositive core. These mode transitions, accompanied by significant changes in electron heating, electron energy distribution function and generation rates of neutral radicals are expected to exert a substantial influence on plasma processing performance.