Heterogeneous Integration of a 0.15μm GaN Circulator and a 45nm RF SOI Voltage-Boosted Clock Generation IC

Advanced CMOS nodes suffer from low linearity due to limited breakdown voltages, while III-V semiconductors offer limited BEOL and integration capability, making it challenging to design complex circuits. Heterogeneous integration of III-V MMICs with CMOS ICs enables the use of the “best junction for the function” to achieve superior dynamic range, but requires tight integration of the ICs with controlled interconnects. This paper presents the first demonstration of a heterogeneously integrated GaN LPTV switched-transmission-line circulator with a CMOS clock generation IC that benefits from the high integration capability of CMOS and superior switch characteristics of GaN. Measurements show 2.5dB DC transmission loss and $\gt17 \mathrm{~dB}$ isolation across $\mathrm{DC}-3.35 \mathrm{GHz}$. It provides 11.8 dBm IP1dB and 23.9 dBm IIP3 thanks to voltage-boosting stacked clock drivers used in CMOS SOI IC. The circulator-clock-chip combo requires only a single-phase external clock at 2.49 GHz instead of complex off-the-shelf multi-phase clocks, making it easy to integrate into system-level applications.