RF inductors with suspended and copper coated thick crystalline silicon spirals for monolithic MEMS LC circuits

Abstract

This letter presents a novel radio frequency (RF) inductor in a monolithic inductor-capacitor circuit developed by using micro-electromechanical systems (MEMS) fabrication technology. The inductor consists of 40-m-thick single crystalline silicon spiral with copper surface coating as the conductor, which is suspended on a glass substrate. The fabricated inductor exhibits a self-resonance frequency higher than 15 GHz, with the quality factor more than 35 and inductance over 5 nH at 11.3 GHz. Simulations based on a compact equivalent circuit model with parameters extracted using a characteristic-function approach have also been carried out for the inductor, and good agreement with measurements is obtained.Index Terms-Copper coating, micro-electromechanical systems (MEMS), monolithic MEMS inductor-capacitor circuit, parameter extraction and simulation, radio frequency (RF) inductor.

High-Q trenched spiral inductors and low-loss low pass filters using through silicon via processes

“…16) Some groups have reported thick metal structures using dielectric cores. [17][18][19] The results in the papers show that thick metal is very effective in improving the Q factor. However, there are two problems in integrating thick spiral inductors.…”

Radio-Frequency Inductors on High-Resistivity Silicon Substrates with a Nanocrystalline Silicon Passivation Layer

“…Both of the two shown spiral inductors have the metal line width of 15 m and inner diameter of 80 m. On-wafer S-parameter measurements were used for the extraction of inductor parameters including inductance and quality factor.After the parasitic de-embedding, the equivalent inductances and quality factors (Q) were extracted by using the Y 11 parameters. At frequencies less than the self-resonance frequency of the inductor, the inductance and Q values of the inductor can be written as follows:26)…”