- 著者
- Baba Masakazu Tsurekawa Sadahiro Watanabe Kentaro Du W. Toko Kaoru Hara Kosuke O. Usami Noritaka Sekiguchi Takashi Suemasu Takashi
- 出版者
- American Institute of Physics
- 雑誌
- Applied physics letters (ISSN:00036951)
- 巻号頁・発行日
- vol.103, no.14, pp.142113, 2013-09
- 被引用文献数
- 29 3
Potential variations around the grain boundaries (GBs) on the surface in undoped n-BaSi2 epitaxial films on Si(111) and Si(001) were analyzed using Kelvin prove force microcopy. The potentials were higher at GBs than those in the BaSi2 grains on Si(111). The average barrier height was approximately 30 meV at the GBs, indicating that the enhanced potentials repulse photogenerated holes so that the charge carrier recombination can be effectively reduced. In contrast, the potentials were smaller at GBs in the BaSi2 on Si(001), and the average barrier heights were approximately 30 and 50 meV along Si[1–10] and [110], respectively.
- 著者
- Nakamura K. Toh K. Baba M. Khan M. Ajmal Du W. Toko K. Suemasu T.
- 出版者
- Elsevier B.V.
- 雑誌
- Journal of crystal growth (ISSN:00220248)
- 巻号頁・発行日
- vol.378, pp.189-192, 2013-09
- 被引用文献数
- 9 4
Al or B layers of a few hundreds of nm in thickness deposited on BaSi2 epitaxial films on Si(1 1 1) substrates were annealed at different temperatures, and the diffusion coefficients of Al and B were evaluated using secondary ion mass spectrometry with O2+. We also investigated the effect of post annealing (850 °C, 10 min) of BaSi2 films on the diffusion coefficients. It was found that both the lattice diffusion and the grain boundary diffusion were decreased by the post-annealing. The plan-view transmission electron microscopy images revealed that the grain size was increased from approximately 0.2 to 0.6 μm by the annealing, and the X-ray diffraction intensities also increased. The activation energies of lattice and grain boundary diffusions in the post-annealed BaSi2 are 0.63 eV and 0.58 eV for Al, and 4.6 eV and 4.4 eV for B, respectively.
- 著者
- Nakamura K. Baba M. Ajmal Khan M. Du W. Sasase M. Hara K. O. Usami N. Toko K. Suemasu T.
- 出版者
- American Institute of Physics
- 雑誌
- Journal of applied physics (ISSN:00218979)
- 巻号頁・発行日
- vol.113, no.5, pp.053511, 2013-02
- 被引用文献数
- 21 11
A 180-nm-thick boron (B) layer was deposited on a 300-nm-thick a-axis-oriented BaSi2 epitaxial film grown by molecular beam epitaxy on Si(111) and was annealed at different temperatures in ultrahigh vacuum. The depth profiles of B were investigated using secondary ion mass spectrometry (SIMS) with O2+, and the diffusion coefficients of B were evaluated. The B profiles were reproduced well by taking both the lattice and the grain boundary (GB) diffusions into consideration. The cross-sectional transmission electron microscopy (TEM) image revealed that the GBs of the BaSi2 film were very sharp and normal to the sample surface. The plan-view TEM image exhibited that the grain size of the BaSi2 film was approximately 0.6 μm. The temperature dependence of lattice and GB diffusion coefficients was derived from the SIMS profiles, and their activation energies were found to be 4.6 eV and 4.4 eV, respectively.
- 著者
- Khan M. Ajmal Hara K. O. Du W. Baba M. Nakamura K. Suzuno M. Toko K. Usami N. Suemasu T.
- 出版者
- American Institute of Physics
- 雑誌
- Applied physics letters (ISSN:00036951)
- 巻号頁・発行日
- vol.102, no.11, pp.112107, 2013-03
- 被引用文献数
- 72 15
B-doped p-BaSi2 layer growth by molecular beam epitaxy and the influence of rapid thermal annealing (RTA) on hole concentrations were presented. The hole concentration was controlled in the range between 1017 and 1020 cm−3 at room temperature by changing the temperature of the B Knudsen cell crucible. The acceptor level of the B atoms was estimated to be approximately 23 meV. High hole concentrations exceeding 1 × 1020 cm−3 were achieved via dopant activation using RTA at 800 °C in Ar. The activation efficiency was increased up to 10%.