Synthesis of submicron metastable phase of silicon using femtosecond laser-driven shock wave

We measured the grain size of metastable phase of Si synthesized by shock compression. We analyzed the crystalline structures of the femtosecond laser-driven shock compressed silicon with x-ray diffraction measurements. We found that submicron grains of metastable Si-VIII exist in the silicon. We suggest that the pressure loading time is too short for the nucleated high-pressure phases to grow in case of the femtosecond laser-driven shock compression, therefore Si-VIII grains of submicron size are obtained. We are expecting to discover other unique crystalline structures induced by the femtosecond laser-driven shock wave. © 2011 American Institute of Physics.Tsujino M., Sano T., Sakata O., et al, Journal of Applied Physics, 110, 12, 126103 (2011) https://doi.org/10.1063/1.3673591

Reactivity between Sn-Ag Solder and Au/Ni-Co Plating to Form Intermetallic Phases

For the formation of micro joint not to melt by secondary reflow soldering, we tried to enhance the reactivity of Sn-Ag solder with Au/Ni20Co plating. It was confirmed that the addition of Co in Ni and existence of Au plating effectively accelerated the reaction and the Sn-Ag solder completely transformed to the intermetallic compounds with a higher melting temperature. Particularly, the addition of Co in Ni changed the interfacial reaction layer from Ni 3 Sn 4 to (Ni,Co)Sn 2 with higher diffusivity of Ni which enhanced the formation of the intermetallic phases. This process is expected to replace the packaging technology using high temperature solders