Characterization of Surface Chemical States of a Thick Insulator: Chemical State Imaging on MgO Surface

Abstract

A study of the beam-foil excitation mechanism using 30-300 keV He+ projectiles. B. Dynefors,l I.Beam-foil excitation functions have been measured for some optical transitions in neutral He (singly as well as doubly excited) and ionized He in the projectile energy range 30-300 keV. The excitation functions have been converted into relative population functions, which for levels within individual level schemes are proportional. The three sets of population functions have been linked by two parameters, one accounting for Rydberg states, and the other accounting for Is core vacancies. The two empirically determined parameters reproduce also charge state distribution data as well as an absolute beam-foil population measurement.The relative level populations have been measured for the nd 3D Rydberg series, n < 11, at 100 keV and at 200 keV and found to be asymptotically close to an r3 behaviour.A search for optical observation of radiative electron capture was performed at 100 keV and 200 keV, the result being negative.

Thermal Oxidation Study on Lead‐free Solders of Sn‐Ag‐Cu and Sn‐Ag‐Cu‐Ge

“…Photoemission spectroscopy has been widely used in the field of surface science for the investigation of material characteristics. [4] Figure 2 shows the oxygen atomic densities of the Sn3.0Ag0.5Cu and Sn3.0Ag0.5Cu0.05Ge alloy solder balls after a five-time reflow. Both alloys had similar oxygen densities on the surface, but after 10 nm sputtering, the Sn3.0Ag0.5Cu0.05Ge alloy's oxygen density decreased to about zero and the Sn3.0Ag0.5Cu alloy's remained about 10 ∼ 20 %.…”