| AVS 56th International Symposium & Exhibition | |
| Applied Surface Science | Wednesday Sessions |
| Session AS-WeA |
| Session: | Angle-resolved X-ray Photoelectron Spectroscopy |
| Presenter: | K. Kobayashi, NIMS Beamline Station at SPring-8, Japan |
| Authors: | K. Kobayashi, NIMS Beamline Station at SPring-8, Japan M. Kobata, NIMS Beamline Station at SPring-8, Japan H. Iwai, NIMS, Japan H. Yamazui, ULVAC PHI Inc., Japan H Takahashi, ULVAC PHI Inc., Japan M. Kodama, ULVAC PHI Inc., Japan M. Suzuki, ULVAC PHI Inc., Japan E. Ikenaga, SPring-8/JASRI, Japan M. Machida, SPring-8/JASRI, Japan J.Y. Son, SPring-8/JASRI, Japan H. Mastsuda, NAIST, Japan H. Daimon, NAIST, Japan H. Nohira, Tokyo City Univ., Japan |
| Correspondent: | Click to Email |
In the course of the development of hard X-ray photoemission spectroscopy (HXPS) using high flux high brilliant undulator X-rays[Nuclear Instruments and Methods in Physics Research A 601 (2009) 32–47], we were convinced that HXPS is a powerful versatile tool for the research in the basic and applied science and technology. This lead us to development of a laboratory ARHXPS system by combining a focused monochromatic CrKα X-ray source, a wide angle acceptance objective lens, and a high kinetic energy electron analyzer. The CrKα source consists of Cr target, 20 keV focused electron gun, and compact bent crystal monochromator. The X-ray spot is variable from 10 μm (1.25 W) to 200 μm (50 W). The wide acceptance objective lens using an ellipsoidal metal mesh electrode is designed by H. Matsuda and H. Daimon [Phys. Rev. E 71 (2005) 066503] . This objective lens is installed in front of a VG SCIENTA R4000 10kV hemispherical analyzer. The total resolution of 0.5 eV was verified by Au Fermi edge measurements. Angle acceptance of ±35 deg with angle resolution of 0.5 deg was confirmed by measuring Au 3d5/2 peak of Au thin strip covered with a hemi-cylindrical multi slit, in angle resolution mode. Seven times enhancement of the throughput was affirmed by comparing intensities of Au spin-orbit doublet peaks with and without the objective lens. The Si1s, Hf3d, and valence band spectra of a HfO2(4 nm)/SiO2 (1 nm)/Si (001) sample were measured to test the practical applicability. Acquisition times of 5 min, 10 min, and 12 hr were found enough to obtain spectra with good S/N ratio. In order to evaluate effect of overlayer on the photoelectron diffraction (XPD), polar-azimuth angle 2D mapping of Si1s intensity of Si(001) substrates was carried out in samples covered with thin natural oxide, 4 nm SiO2, and 7 nm SiO2. It was verified that XPD intensity modulation was clearly observed even in the 7 nm SiO2 overlayer substrate. Another trial was to detect chemical change in buried interface of an Ir (10 nm)/HfO2 (2.2 nm)/wedge shape SiO2 (0-10 nm) /Si (100) sample. The Si1s (both substrate and oxides) and O1s spectral shapes were found to change along the thickness variation of the wedge.
In conclusion, the CrKα laboratory ARHXPS system was verified to be a promising tool for the investigation of bulk and thin solid film materials. The potential applicability of the system to the depth profiling of layered materials of more than 10 nm thickness is to be realized. Strong XPD modulation of the crystalline substrate may causes a certain difficulty to the depth profile analysis
We are thankful to Dr. Miyata and Dr. Abe of AIST for providing us Ir/HfO2/SiO2/Si(001) sample.