High Q-factor monolithic inductor for RF devices using double ground shield

This paper presents a technique to improve RF integrated inductor performance, incorporating double ground shield using polysilicon and n+ buried layer, providing a fully shield and preventing the electric field penetration. This method was compared with conventional inductors, patterned ground shield, double ground shielding using polysilicon inductors, and improves Q-factor up to 50% at 3.5, 4 and 5 GHz. The results were obtained based on AMS 0.35μm BiCMOS technology. This technique can be applied to any BiCMOS technology without any additional process.