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The cross sections of the $^{7}\mathrm{Be}(n,\ensuremath{\alpha})^{4}\mathrm{He}$ reaction for $p$-wave neutrons were experimentally determined at ${E}_{\mathrm{c}.\mathrm{m}.}=0.20--0.81\text{ }\text{ }\mathrm{MeV}$ slightly above the big bang nucleosynthesis (BBN) energy window for the first time on the basis of the detailed balance principle by measuring the time-reverse reaction. The obtained cross sections are much larger than the cross sections for $s$-wave neutrons inferred from the recent measurement at the n_TOF facility in CERN, but significantly smaller than the theoretical estimation widely used in the BBN calculations. The present results suggest the $^{7}\mathrm{Be}(n,\ensuremath{\alpha})^{4}\mathrm{He}$ reaction rate is not large enough to solve the cosmological lithium problem, and this conclusion agrees with the recent result from the direct measurement of the $s$-wave cross sections using a low-energy neutron beam and the evaluated nuclear data library ENDF/B-VII.1.

Embedded silicon carbon alloy (e-Si:C) technology for source and drain (S/D) is expected to improve nMOSFET drive current. The distribution and activation characteristics of arsenic in Si:C film and the interfacial solid-phase reaction of the Ni/Si:C system were studied with the aim of achieving the maximum improvement of the characteristics of e-Si:C S/D. It was clarified that the active carrier concentration of Si:C decreased with increasing carbon concentration compared to the control Si. There is concern that the low doping activation in Si:C increases series resistance of e-Si:C S/D nMOSFETs and degrades the performance gain expected from the strain effect.

The impacts of source and drain (S/D) doping on device performance in embedded SiGe (e-SiGe) p-channel metal–oxide–semiconductor field-effect transistor (pMOSFET) are presented. An in situ boron-doped e-SiGe S/D device exhibits higher drive current than a boron-implanted e-SiGe S/D device owing to its enhanced hole mobility and reduced parasitic resistance. The precise control of the recessed Si shape and the SiGe proximity to the channel is essential for utilizing the intrinsic benefit of an in situ boron-doped e-SiGe S/D. Moreover, it was confirmed that the channel stress induced by e-SiGe S/D increases as MOSFET size decreases. This indicates that the use of in situ boron-doped e-SiGe S/D is a promising technique for 32 nm node pMOSFET.

Carbon nanostructures (CN) have been selectively grown directly onto the top of nickel ion implanted nanopyramid array (Ni NPA) by the plasma enhanced chemical vapor deposition (p-CVD) technique. Firstly, NPA were fabricated by taking advantage of the anisotropic etching characteristics of silicon in hydrazine (N 2 H 4 H 2 O); where the ion implanted area acted as a mask for hydrazine etching. Secondly, carbon nanostructures were grown on Ni NPA by feeding methane/hydrogen (CH 4 /H 2 ) mixtures into p-CVD reactor. The change of concentration ratio of methane to hydrogen dramatically affected the growth selectivity of CN. Methane concentrations lower than 20%, promoted the selective growth of CN on the top of Ni NPA. Morphology and chemical nature of grown species were studied by employing scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) spectroscopy, respectively.