Three-Dimensional Substrate Impedance Engineering Based on<tex>$hbox p ^-$</tex>/<tex>$hbox p ^+$</tex>Si Substrate for Mixed-Signal System-on-Chip (SoC)

Theoretical studies of displacement deposition of nickel into porous silicon with ultrahigh aspect ratio

“…It also finds use in fabrication of highly sensitive surface-enhanced Raman scattering substrates [13,14]. Recently, this technique was explored as a means to create a substrate impedance architecture for microwave isolation in mixed-signal integrated circuits [18]. Such architecture can be fabricated by etching a porous region of pore size 1-2 m and depth ∼200 m on a Si substrate, followed by depositing metal into the pores.…”

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

“…Such configuration has shown promising results. Cross-talk test structure based on a p − /p + Si substrate and detailed study was described much more thoroughly in another of our earlier publications [5] and only a brief discussion is presented here. The metalized macroporous moat through p − layer has a width of 50 µm and was connected to the upper ground planes via oxide windows and the p + layer beneath.…”

“…Its true effectiveness is however underestimated as an isolation structure. Our simulation result shows that the predicted RF cross-talk reduction using a typical metal trench can be as effective as −100 dB at 40 GHz (Metal moat (S)) [5]. …”

“…As a result, we made use of this approach to incorporate the resultant moat into the p − part of the Si substrate in our test circuit structure for cross-talk isolation [5]. Two port S-parameters were measured using a HP8722ES network analyzer up to 40 GHz.…”

“…PS is an ideal material for cross-talk isolation in mixed signal integrated circuits because of its high resistivity (>10 6 Ω-cm) [4] and its near perfect thermal expansion coefficient match to bulk Si. To further reduce crosstalk, a highly conductive moat was predicted by simulation to shield RF cross-talk [5]. The conductive moat also serves as “true ground” contacts, i.e ., contact points on the chip surface with much reduced inductance to the true system ground.…”