A flexible mixed-signal/RF CMOS technology for implantable electronics applications

A novel post-CMOS fabrication process has been developed to transform a 0.18 μm 1P6M mixed-signal/RF CMOS (complementary metal oxide semiconductor)-integrated circuit chips fabricated on an 8 inch SOI (silicon-on-insulator) wafer into flexible devices sandwiched between biocompatible material (10 μm parylene-C on both sides in this case) and enables future implementation of implantable and fully integrated electronic devices. The functionality of the flexible integrated circuits is demonstrated by a low phase noise RF CMOS VCO (voltage-controlled oscillator) circuit in a ring oscillator configuration that operates at a few hundred MHz to GHz. We report here the associated post-processing technology to make these flexible IC chips and the characterization of both MOS transistors and the demonstration circuit on the flexible IC chip under bending stresses.