Signal isolation in BiCMOS mixed mode integrated circuits

Comparing several cross-talk reduction schemes using two-dimensional device simulation and measurements on silicon has shown that while SOI based processes provide high isolation from cross-talk, fully junction isolated wells can provide equal or better cross-talk immunity at a lesser expense. Simple guard ring substrate contacts appear to be the technique best suited for preventing cross-talk at high operating frequencies. A lumped parameter equivalent circuit has also been developed to simulate fully junction isolated wells in SPICE.