Simulation and Optimization of High Performance On-Chip Solenoid MEMS Inductor

In this paper, we proposed a vertical spiral structure to realize high performance (high Q and high L) on-chip inductor based on MEMS technology. It aims to reduce the substrate loss by the approach of 3D vertical integration so that the quality factor of the on-chip inductors could be improved. In order to verify and explore the improvement of the quality factor of the vertical spiral solenoid structure, finite element method was used to analysis the performance of designed inductor, and an optimal solution was raised through modeling and simulation by commercial software HFSS. Combining the thermal oxidation process level, we tried to isolate silicon by 10um silicon dioxide isolation layer. Simulation results show that more than 10um silicon dioxide isolation layer no longer improves the inductive performance. The simulation results show that the same scalar-isolated vertical spiral inductors provide superior performance (peak Q = 32 @ 7 GHz, L=4nH). Compared with ordinary silicon planar inductors, the quality factor Q increased 30%, inductance L increased 100%. In addition, self-resonant frequency is greater than 10 GHz which makes our inductor could adapt to a wider spectrum of applications.