Experimental evaluation of CaO, SrO and BaO sputtering yields by Ne⁺ or Xe⁺ ions

Abstract

Barrier coating materials used in plasma display panel (PDP) cells strongly affect the discharge voltages. Although magnesium oxide (MgO) is widely used for barrier coating in the current generation of commercial PDP cells, other alkaline earth oxides have been studied as alternatives and indeed some of them are now known to have lower discharge breakdown voltages for PDP cells, which would increase the energy efficiency of the cells. On the other hand, the resistance against physical sputtering is another critical parameter for barrier coating. In this work, sputtering yields of CaO, SrO and BaO by monochromatic Ne or Xe ion beams are obtained experimentally as functions of beam energy in the range 100–300 eV. Despite the large differences in mass among the targets and incident ions, sputtering yields are found to be similar in magnitude among them for a given incident energy.

Monte Carlo simulations of noble gas ion beam sputtering yield of MgO, CaO, SrO, and BaO with various thin coatings in AC‐PDP cells

“…In this subsection, the relative difference between the sputtering yields of CaO, SrO, and BaO thin films computed by SRIM and experimental data is plotted in Figure . This figure shows the relation between sputtering yield (At./ion) and ion energy (eV) of two Ne + and Xe + ions at normal incidence.…”

“…Then, in our calculations, the input densities of MgO, CaO, SrO, and BaO were 3.4, 3.34, 5.04, and 5.99 g/cm 3 , respectively, the mass of which was 40.3, 56.1, 103.6, and 153.3 amu, respectively, and the input thickness of the films was typically 5000 except the MgO having a thickness of 10 000 . As an input for E s of these protective layers, we have generally used the heats of sublimation, which were 6.73, 7.16, 6.29, and 4.8 eV, respectively, the same values as listed in Yoshimura et al However, experimental densities for different compounds were unavailable for α‐Al 2 O 3 /XO, TiO 2 /XO, and Al 2 TiO 5 /XO (X = Mg, Ca, Sr, and Ba). Hence, the densities were calculated using the equation expressed as follows: …”

“…This energy is usually taken to be equal to the heat of sublimation . Experimentally and theoretically, several research groups have found that sputtering yields depend on the parameters of both the incident ion beam and the material.…”

“…Other materials have been proposed as a protective layer instead of MgO in order to reduce the discharge voltage further, such as alkaline earth metal oxides (CaO, SrO, and BaO) and their mixtures . Nevertheless, these materials are extremely reactive with H 2 O and CO 2 in the air atmosphere, forming hydroxides and carbonates, respectively .…”

“…In Section , we describe the background information about the computational methodology. In Subsection , we compare our numerical simulations with experimental results on sputtering yields of MgO, CaO, SrO, and BaO to extract the E s . Subsection is devoted to the presentation and discussion of the obtained results.…”