Novel isolation structures for TFSOI technology

Novel isolation structures are reported to improve the cross-talk isolation between active devices as well as the performance of on-chip inductors in a thin-film SOI (TFSOI) technology. In these structures, p/sup +/ substrate contact rings and appropriately doped TFSOI layers are used. The p/sup +/ substrate contact rings provides -57 dB isolation (typically characterized for a device spacing of 100 μm) at 10 GHz, which is the best ever reported in TFSOI technology. A maximum Q-factor of 10.4 is obtained for TFSOI-layer shielded on-chip inductors. The inductor-to-inductor isolation is -62 dB (for a spacing of 100 μm) at 10 GHz, which is close to the ideal isolation of the open probes. This excellent cross-talk isolation performance and the high-Q on-chip inductors make the TFSOI technology a very suitable candidate for mixed signal RF system-on-a-chip (SOC) applications.