Study of Ni Metallization in Macroporous Si Using Wet Chemistry for Radio Frequency Cross-Talk Isolation in Mixed Signal Integrated Circuits.

A highly conductive moat or Faraday cage of through-the-wafer thickness in Si substrate was proposed to be effective in shielding electromagnetic interference thereby reducing radio frequency (RF) cross-talk in high performance mixed signal integrated circuits. Such a structure was realized by metallization of selected ultra-high-aspect-ratio macroporous regions that were electrochemically etched in p- Si substrates. The metallization process was conducted by means of wet chemistry in an alkaline aqueous solution containing Ni2+ without reducing agent. It is found that at elevated temperature during immersion, Ni2+ was rapidly reduced and deposited into macroporous Si and a conformal metallization of the macropore sidewalls was obtained in a way that the entire porous Si framework was converted to Ni. A conductive moat was as a result incorporated into p- Si substrate. The experimentally measured reduction of crosstalk in this structure is 5~18 dB at frequencies up to 35 GHz

Study of Ni Metallization in Macroporous Si Using Wet Chemistry for Radio Frequency Cross-Talk Isolation in Mixed Signal Integrated Circuits.

A highly conductive moat or Faraday cage of through-the-wafer thickness in Si substrate was proposed to be effective in shielding electromagnetic interference thereby reducing radio frequency (RF) cross-talk in high performance mixed signal integrated circuits. Such a structure was realized by metallization of selected ultra-high-aspect-ratio macroporous regions that were electrochemically etched in p- Si substrates. The metallization process was conducted by means of wet chemistry in an alkaline aqueous solution containing Ni2+ without reducing agent. It is found that at elevated temperature during immersion, Ni2+ was rapidly reduced and deposited into macroporous Si and a conformal metallization of the macropore sidewalls was obtained in a way that the entire porous Si framework was converted to Ni. A conductive moat was as a result incorporated into p- Si substrate. The experimentally measured reduction of crosstalk in this structure is 5~18 dB at frequencies up to 35 GHz

Study of Ni Metallization in Macroporous Si Using Wet Chemistry for Radio Frequency Cross-Talk Isolation in Mixed Signal Integrated Circuits

A highly conductive moat or Faraday cage of through-the-wafer thickness in Si substrate was proposed to be effective in shielding electromagnetic interference thereby reducing radio frequency (RF) cross-talk in high performance mixed signal integrated circuits. Such a structure was realized by metallization of selected ultra-high-aspect-ratio macroporous regions that were electrochemically etched in p− Si substrates. The metallization process was conducted by means of wet chemistry in an alkaline aqueous solution containing Ni2+ without reducing agent. It is found that at elevated temperature during immersion, Ni2+ was rapidly reduced and deposited into macroporous Si and a conformal metallization of the macropore sidewalls was obtained in a way that the entire porous Si framework was converted to Ni. A conductive moat was as a result incorporated into p− Si substrate. The experimentally measured reduction of crosstalk in this structure is 5~18 dB at frequencies up to 35 GHz

CH4-CO2 replacement occurring in sII natural gas hydrates for CH4 recovery and CO2 sequestration

The CH4 center dot CO2 replacement occurring in sII natural gas hydrates for CH4 recovery and CO2 sequestration was investigated with a primary focus on thermodynamic, microscopic, and kinetic aspects. The guest-exchange behavior during replacement and the end-state composition analysis of replaced hydrates demonstrated that the extent of the replacement after CO2 injection into the sII CH4 + C3H8 hydrate was significantly enhanced with an increase in the injected CO2 pressure (P-CO2). The structure identification using powder X-ray diffraction (PXRD) suggested that the higher extent of replacement at higher P-CO2 was closely related with the higher portion of sI hydrate after replacement. C-13 NMR spectroscopy confirmed that most of the CH4 molecules resided in the small cages of the replaced sII hydrate while small amount of them also existed in the CO2-rich sI hydrate after replacement. The dissociation behavior and dissociation enthalpies of the replaced hydrates examined using an HP mu-DSC also verified the structural coexistence of sI and sII hydrates after replacement. The overall results can offer the first experimental evidence of the relationship between the replacement efficiency and the partial structure-transition in the CH4 + C3H8 - CO2 replacement, and can provide further insights into the cage-specific occupation of external gas molecules and thermal property changes for the actual replacement occurring in sII natural gas hydrates