Study of Ni metallization in macroporous Si using wet chemistry for radio frequency cross-talk isolation in mixed signal integrated circuits

Xi Zhang*, Chengkun Xu, Kyuchul Chong, King-Ning Tu, Ya Hong Xie

*Corresponding author for this work

Research output: Contribution to journalArticle

1 Scopus citations

Abstract

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.

Original languageEnglish
Pages (from-to)952-962
Number of pages11
JournalMaterials
Volume4
Issue number6
DOIs
StatePublished - 1 Dec 2011

Keywords

  • Macroporous Si
  • Ni metallization
  • RF cross-talk isolation

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