Electron temperature control in low-pressure plasmas using a two-mesh-separation technique

Independent control over the electron temperature and ion bombarding flux has been achieved in weakly ionised discharge through the use of two electrically biased meshes. The meshes divide the discharge into two parts; a main RF plasma and de processing plasma, the latter is sustained through controlled diffusion of particles from the main plasma. By varying the bias to each of the grids separately, and at typical pressures of 2.6 Pa in the processing chamber, the electron temperatures can be varied in the range 0.2-5.6 eV. To an electrically isolated surface, the ion bombarding fluxes can be controlled between 0.2 and 5.4 x 10(18) m(2) s(-1). This method of electron temperature control, which gives more flexibility than the single grid separation technique, allows ion energies to be varied from 1 to 27 eV, independently of the ion flux. This is useful, both for the fundamental study of plasma-surface interactions and for developing discharges with controlled parameters to tailor the properties of materials such as polymeric surfaces. (C) 2003 Elsevier Science Ltd. All rights reserved.