Study on Large-Inductance Inductors Using Double-Layer Coils on HR Substrate

A large-inductance inductor using double-layer coils on HR (high-resistance) substrate is presented. The design is based on the analytical equation of mutual inductance and the current direction of the coils on different layers. The inductor is realized with a micro-machined process which is compatible with standard CMOS process. To evaluate the performance of double-layer coil inductor, a single-layer inductor with the same structural and process parameters is also designed and fabricated. Measurement results give inductance of 7.7nH at 1GHz for double-layer inductor and 2.2nH at 1GHz for single-layer one. The measured Q (quality factor) of 9.6 at 0.8GHz and self-resonance frequency of 2.2GHz indicates that it is applicable for VHF/UHF applications