Micro-Inductor and Capacitor

Micro-Scaled on-chip 30-turn Toroidal Inductor


This SEM image shows the micro-scaled on-chip 30-turn toroidal inductor fabricated on SiO2-coated Si substrate by standard photolithography technique. The diameter denoted in D of the inductor is 240 μm. A 160 nm thick ring-shaped core of SiO2 is used to isolate top metal (Au, 220 nm) and bottom metal (Au/Cr, 35 nm/5 nm). Ground-signal-ground pads are designed for high frequency measurement. The best inductor shows the maximum quality factor of 183 at an operating frequency of 28.8 GHz, in which the D and the dielectric layer thickness are 960 μm and 5 μm, respectively. Details please consult with Professor Wu, and refer to the paper submitted IEEE Transitions on Magnetics.

This SEM images demonstrate a novel on-chip 3-D inductor fabricated on pre-etched silicon substrate. The 3-D inductor was defined using electron beam lithography and sequentially metalized through lift-off process. In our system, the focus of the electron beam as a function of the depth of the etched silicon substrate was carried out by tuning the focal plane automatically to accomplish 3-D electron beam exposure. Details please consult with Professor Wu, for more information.