Particle flux and energy distributions in electron beam-produced ion-ion plasmas

Summary form only given. Ion-ion plasmas are thought to prevent device damage and isotropic etch profiles resulting from localized surface charging in conventional electron-ion plasma processing. The advantage of ion-ion plasmas is derived from the ability to deliver anisotropic fluxes of both positive and negative ions to the substrate surface. We present the results of experiments aimed at forming electron beam-generated ion-ion plasmas. Temporally resolved ion flux and energy distributions are reported for pulsed plasmas produced in Ar/SF/sub 6/ mixtures. Positive and negative ions were extracted from the plasma by applying a low frequency, low voltage, square wave bias to an electrode located adjacent to the plasma. Supporting Langmuir probe and microwave absorption measurements are also reported to give a more complete description of the ion-ion character in these plasmas. The results are compared to those from electron-ion plasmas produced by the same high-energy electron beam in non-halogen gases. The appropriate gas phase kinetics are discussed as well as the experimental requirements needed to produce ion-ion plasmas.