篭島 靖

We have demonstrated to form an x-ray microbeam with a narrow angular divergence in both vertical and horizontal polarization directions of synchrotron radiation x-rays by the use of successive asymmetric Bragg reflections. Using the highly parallel x-ray microbeam thus obtained, we are able to analyze the local minute strain of less than 10^<-5> in semiconductor materials and devices. A series of x-ray rocking curves have been obtained by scanning the sample against the x-ray microbeam. Variations of the reflection peak intensity, angular shift value and/or half widths inform us how strain is distributed in the materials with high spatial resolution. In addition, reciprocal space maps have been drawn with an analyzer crystal put behind the sample on the x-ray path. From those data, strain distribution can be analyzed in terms of both lattice tilt variation and lattice parameter variation independently. Strain near Si-oxide film edges on Si substrate or that in silicon-on-insulator (SOI) crystals or other semiconducting materials has been measured. The results of reciprocal space maps have shown that the strain in the bonded SOI layers is mainly due to the lattice tilt variation rather than the lattice parameter variation.

Utilizing synchrotron radiation from SPring-8, an X-ray microbeam with a narrow energy bandwidth and a small angular divergence has been developed. Using the X-ray microbeam, we have demonstrated to measure very local and minute lattice strain in various semiconducting materials after some wafer preparation processes or device fabrication processes. Local strain in a Si crystal around the SiO_2/Si film edges and that in top Si layers of silicon-on-insulator (SOI) crystals are discussed as sample materials.

我々は、放射光を用いた屈折イメージングの臨床の可能性を検討中である。本稿では, サンプルと冷却CCDの間の距離を10、5および0.1mにセット・アップした。距離を離すほど散在線は顕著に減少し、コントラストが改善された。空間分解能はテストチャートを用いて80ミリレムの被爆量で36マイクロメートルであった。また人間の頭蓋骨(同じ被爆量)と手のファントム(約20ミリレム)の画像を取得した。それらの画質は、同じ被爆量で臨床画像と比較して非常に改善された。放射光を用いたシンプルなイメージングの臨床における可能性を示す。