Plasma etching dynamics of CaxBa1?xNb2O6 (CBN) material
This work reports an extensive study on the etching of Calcium Barium Niobate (CBN, a novel electro-optical material), using high density plasma processes. Different plasma chemistries (inert, chlorine and fluorine plasmas) are used to etch Ca0.28Ba0.76Nb2O6 (CBN-28) thin films at pressures going from 1 to 10mTorr, bias voltages going from 0 to 600V and substrate temperatures ranging from ?75 to 375C. For all the conditions investigated, the experimental data are compared with a simple sputtering model and completed with TOF-SIMS measurements of some of the samples processed. This study shows that there is no chemical enhancement or inhibition in the case of chlorinated plasma (Cl2) regardless of the ion energy or the substrate temperature. In the case of an SF6-Ar plasma, it is shown that the observed increase of the etch yield above 150C results from a reduced inhibition as the temperature increases, this inhibition being caused by F and F2 species adsorption at the surface of the material.
plasma etching cbn electro-optic icp