Volume 25(2) - Summer 2009

Recently, there are a very large number of electric devices developed in the high-tech industry. Semiconductor material is one of the basic components for these electronic devices. For example, III–V compounds (GaN, GaAs, etc.) are often used to produce optical devices because the band gap range of these compounds are close to the visible light range. These compounds can coordinate band gap making a solid solution with another III–V compound. For instance, GaN can adjust the luminescence wavelength and the refractive index by making solid solution with In or Al. As a result, these compounds can be applied to electronic devices such as blue light emitting diodes, semiconductor lasers, etc.

In the development of these materials, it is important to obtain the correlation between device performances and their physical properties. X-ray diffraction method is commonly used to obtain information about physical properties, including composition and thickness of a thin film and orientation relationship between the film and its substrate.

Two of the most basic semiconductor components in many electronic devices are an epitaxial film and its perfect single-crystal substrate. X-ray dynamical theory can be used to study perfect single-crystal materials. The dynamical diffraction theory is different from conventional X-ray diffraction theory used for the studying of a polycrystalline sample as well as an imperfect crystal. To apply this theory, the conventional X-ray powder diffraction method, which is used for studying polycrystalline samples, is not sufficient, and the high-resolution X-ray diffraction method is required.

In this article, high-resolution diffraction method mainly used for the characterization of semiconductor materials and single crystal substrates is explained.
 

X-ray diffraction (XRD) and differential scanning calorimetry (DSC) are widely used to measure changes in physical and chemical states, such as phase transition, crystallization, dehydration, and decomposition, in solid substances. Rigaku Corporation’s simultaneous measurement instrument for XRD and DSC (hereafter referred to as the XRD-DSC) is configured with a general-purpose X-ray powder diffractometer and a DSC as an attachment. As an instrument capable of providing information on thermal and structural changes in a single measurement, it has won high regard in research and development involving pharmaceuticals, complexes, liquid crystals, catalysts, high polymers, and electronic materials. This paper introduces the features of the XRD-DSC and the latest data obtained using a highspeed one-dimensional X-ray detector.
 

X-ray Rocking Curve (XRC) analysis is widely used with high resolution XRD systems for the evaluation of the layer thickness and periodicity of multilayer thin films, or for the composition of films in solid solution systems (also called mixed crystals). These parameters are crucial to the performance of electronic and optoelectronic device applications such as Si-Ge systems, GaAs-AlAs system, etc.

XRC analysis requires specialized software to compare the raw data with the calculated intensity profiles. It was not an easy task to find a best-fit model due to the wide variation of layer parameters, such as layer thicknesses, composition, strain, etc. — a simple least-square optimization procedure would have easily fallen into the traps of models with locally optimized states. In contrast, with the ever-increasing variation of functional thin film materials, an XRC analysis technique must be applicable to new material systems.

Here, Rigaku presents a sophisticated and powerful new XRC analysis program to respond to these requests.  GlobalFit (Extended Rocking Curve Analysis) is equipped with a powerful fitting/optimizing algorithm and an expanded flexibility for applications in a wide range of material combinations.
 

Rigaku’s multi-channel X-ray fluorescence spectrometer, Simultix, has been widely used for production control in fields such as the steel and cement industries, where rapid and precise analyses are required. We have developed a new model, the Simultix 14, in which performance, functionality and software user interface are greatly improved compared to the former model.  The Simultix 14 can be connected to automated sample preparation apparatus for on-line operation. The Simultix 14 has been developed with a focus on fast, accurate analysis and reliability. Fully utilizing Rigaku’s accumulated X-ray technologies, the features of the Simultix12 have been improved and extended in the Simultix 14.

According to the International Confederation for Thermal Analysis and Calorimetry (ICTAC), thermal analysis is a group of techniques in which the material to be analyzed is subjected to a defined temperature program, and the change in the physical/chemical property of the material is measured as a function of temperature and/or time. In the defined temperature program, the temperature is controlled and programmed as a function of time, temperature change per unit time (i.e., heating rate, °C/min) or the holding time at a fixed temperature. On the other hand, the control system in the controlled-rate thermal analysis (CRTA) is not the temperature but the rate of change in a sample. For example, the sample’s mass-loss rate in the controlled-rate TG (or Dynamic TG) or the rate of change of a dimension (e.g., the contraction rate) of a sample in the controlled-rate TMA (or Dynamic TMA) is controlled and measured as a parameter in this technique.
 

Owing to the recent developments in emerging nations, the consumptions and, therefore, the productions of cement are increasing rapidly. Worldwide demands for benchtop X-ray fluorescence spectrometers, as main analyzing systems in medium-size cement factories or as backup systems in large factories and laboratories, are rising very quickly.

Since Supermini is a benchtop wavelength dispersive X-ray fluorescence (WDX) spectrometer equipped with an air-cooled X-ray tube and without the need of using cooling water, it meets such demands. Supermini offers the XRF analysis with high precision and sensitivity even for light elements, which are the most well-known features of a WDX spectrometer over an Energy dispersive X-ray fluorescence (EDX) spectrometer.

 Results on a cement analysis using Supermini according to the U.S. ASTM (American Society for Testing and Materials) C114 standard test as well as the Japanese JIS R5204 “Chemical analysis method of cement by X-ray fluorescence” method, are reported and discussed.