X-ray photoelectron spectroscopy (XPS) is known to be one of the relatively low destructive surface analysis techniques. Surface changes of the samples during the XPS measurements are often observed. This change called surface degradation has at present no standard to determine its extent. In this report, we have carried out several “round-robin” tests to investigate this phenomena, and the relative X-ray dose parameter that represents the intensity of the Ag3d5/2 peak multiplied with the measurement time was found to be important in the XPS spectra analysis. This article describes the methods for the evaluation of the surface degradation of the samples during the XPS measurements.
XPS or AES sputter depth profiling sometimes encounters difficulties with the materials that are damaged by ion bombardment. Therefore, it becomes difficult to determine precise chemical states of such materials. The damages of oxides by ion bombardment as observed in XPS spectra were reviewed. Spectrum changes are classified into three types; (1) additional peaks appear as a result of reduction for one type of the oxides, (2) the spectra are broadened for the second one, and (3) the third type oxides are not chemically changed. It is pointed out that these changes are related to the change of the enthalpy of atomization and ionicity. Secondly, the intensity changes as a function of sputtering time is formulated using reduction cross sections by the ion bombardment and sputtering yield.
It is well known that ion sputtering induces surface damages on compound semiconductors. These damages are observed as the surface composition and the surface topography changes the extent of which depends on the kinds of materials. For example, indium islands on an argon ion bombarded InP surface grow due to the nucleation kinetics of free indium atoms created by preferential sputtering. Here we report the topics of the surface damage.
In order to determine the extent of electron irradiation damage on silicon dioxide quantitatively, a simple method of measuring the decomposition cross section of SiO2/Si samples from the Si LVV intensity peaks has been proposed. A 100 nm SiO2 film on Si, damaged by the electron irradiation at primary electron energies of 3, 5, 10 and 15 keV was studied. As a result, CDE(critical dose electrons) were able to be determined from the curve fit to Si LVV metallic peaks from the 2-stage exchange equation. The primary electron energy dependence of CDE for SiO2 could be described by Dc(critical dose electrons) ∝ lnEp(primary electron energy).
The electron irradiation to non-conductive materials causes building up of surface charge that makes the electron probe analysis, such as AES or EMPA, difficult. On the other hand, small area analysis is needed increasingly especially for insulating portions of semiconductor devices and ceramics (sapphire, quartz glass and so on). Therefore, charge compensation in AES analysis that provides high special resolution has becomes important. This paper introduces the conventional charge compensation methods and shows some applications of using the low energy ion irradiation method.
Specimen damage due to electron beam irradiation is a serious problem for EPMA/SEM observation, which is caused by heat produced in the process of inelastic scattering of incident electrons. The produced heat is in proportion to the specimen current and accelerating voltage and is in inverse proportion to the beam diameter. The thin film method using this substrates for the soft materials is effective to avoid the electron beam damage. Several effective methods to suppress the specimen damage are presented and discussed by using real examples.
The diamond-like carbon (DLC) films were prepared from methane, benzene and toluene by thermal electron exited plasma CVD method. Micro-laser Raman analysis of three films showed a typical spectrum of DLC film. The hardness and hydrogen content of the film were 11−25 GPa and 23−29 at%, respectively. The tribological properties of three DLC films were investigated using a scratch tester, a Bowden-Leben type friction tester and a ball-on-disk type reciprocating friction tester. The effects of raw materials on the tribological properties were confirmed. The difference in tribological properties of these three films seems to be related with their hardness. That is, the friction coefficient of the DLC film with low hardness was lower than that of the film with high hardness. On the other hand, when the hardness was increased, the specific wear rate of the DLC films appeared to decrease. The transferred films formed on mating material surfaces are supposed to play significant roles in the tribological properties of the DLC films.
The important functions for make-up foundation are 1) concealing flaws such as pores, spots and wrinkles, 2) providing a beautiful skin color and texture and 3) UV-protection. Furthermore, the foundation requires considerably long-lasting finish, smooth sensation when spreading onto skin, and so on. In recent years, various demands for these performances are greatly growing and many advanced technologies have been developed and applied to make-up cosmetic products. New technologies for make-up foundation, related to surface science and nano materialsare briefly mentioned.