Electron Interactions With Plasma Feed Gases

Abstract

Major feed gases for plasma generation of F atoms are CF 4, SF 6 and NF 3. The etching process is determined by creation of F atoms through Dissociative Electron Attachment of CF 4 and by dissociation of CF 4 molecule through electronic excitation and ionization. Hence the estimation of excitation as well as ionization cross sections of e-molecule processes are required. Radicals of feed gases (CFx etc.) play important role in anisotropic etching. Also, restriction of emission of Perfluoro compunds and Global Warming Potential stimulates changes in feed gases. Therefore electron impact studies including computation of various cross sections and investigation of anion formation and resonances are major areas of interest. In this work we report various electron impact total cross sections, resonances and target properties for plasma feed gases and fluoro compounds over an extensive range of impact energies (0.1 eV - 5000 eV). Below 15 eV, we use ab-initio calculations with fixed nuclei approximation employing the molecular R-matrix method 1 and above the threshold of the target we employ the well-established Spherical Complex Optical Potential formalism 2.