Hard X-ray photoelectron spectroscopy (HAXPES) has recently attracted attention for its unique capabilities. High energy X-ray enables to excite deep core level electrons and in parallel the information depth from the sample surface is significantly larger than conventional XPS, which enables to investigate electronic structures beneath the sample surface and buried interface without destructive ion etching. Although most of the previous HAXPES studies have been conducted with synchrotron radiation source, laboratory HAXPES is getting more and more attracted in practical applications. In this review, we report unique capabilities of the laboratory HAXPES with our recent applications, which has both of soft and hard X-ray as excitation sources.
AES and XPS have been used to analyze the top surface of a solid sample for a long time. In late years scientific reports including an AES result became less than those of XPS year by year. It originates in superior several points of XPS; easy non-conductive sample analysis, quantitative analysis with higher accuracy, and excellent chemical state analysis. However, AES can acquire additional information from a minute area of a few tens of nm, which cannot be attainable by XPS. It was usually very important to understand a true sample surface condition more deeply. We have done lots of Auger applications for a long time, in order to extend AES capability to analyze many kinds of samples. In this report, we introduce recent applications of AES; non-conductive sample analysis and chemical state analysis. They are useful techniques and can be applied to many practical samples.
Elemental identification of unknown mass/charge peaks is one of the capabilities required by corporate users who are in charge of time-of-flight secondary ion mass spectrometry (TOF-SIMS). An accurate mass scale is essential to identify the unknown peaks. A conventional method for the mass scale calibration that uses only low-mass CXHY fragment ions does not provide precise relative mass accuracy to high-mass peaks. On the other hand, a novel method using molecular ions of internal additives is shown to improve the relative mass accuracy of high-mass peaks.
The shape and structure, component distribution of nano-scale areas have significant effect on the property of materials in a variety of fields. SIMS is a surface analytical method for measuring the mass-to-charge ratio of the secondary ions generated by the irradiation of an ion beam to the surfaces. It is possible to obtain the mass image of nano-scale area by scanning an ion beam of several tens of nm size and by detecting secondary ions effectively. Such instrument is called “Nano-SIMS”. It is a powerful tool that can evaluate the relationship between the structure and component distribution and physical properties in the various fields. In this paper, we describe the concept and introduction of instrument, application of itself and the future prospects for Nano-SIMS.
X-ray Photoelectron Spectroscopy (XPS) is a powerful tool for direct observation of chemical state of materials. Various kinds of instruments that are optimized for high energy resolution, high angular resolution, or high spatial resolution are developed and are used according to each applications. In general, XPS measurements are performed with the condition of high or ultra-high vacuum due to the attenuation length of X-ray and photoelectrons. At higher pressure, there is also a difficulty to apply high voltage to the XPS analyzer. On the other hand, demands for in-situ measurement are increasing. We have developed instruments for Near Ambient Pressure X-ray Photoelectron Spectroscopy (NAP-XPS) recently and some of them are already used at several institutes. Latest results and the future prospect of NAP-XPS are described in this article.
Secondary ion mass spectrometry (SIMS) and X-ray photoelectron spectroscopy (XPS) have been used for the analysis of inorganic and organic materials. Recently, cluster ion beams have been utilized for the etching of organic materials for depth profiling in SIMS and XPS, and ionization in SIMS. In this paper, recent studies on different types of cluster ions for SIMS and XPS will be reviewed and summarized.