Monolithic high-performance three-dimensional coil inductors for wireless communication applications

An on-chip three-dimensional RF coil inductor is proposed as a key component to implement monolithic wireless transceivers. The device achieves a substantially superior performance compared to conventional spiral inductors, and is amenable to monolithic integration in a standard IC process due to its low thermal budget. Experimental devices fabricated on a standard silicon substrate (10 /spl Omega/-cm) achieve a 2.6 nH inductance with a peak quality-factor (Q) of 13 at 900 MHz. The Q-factor is limited by a lossy adhesive used in the fabrication. In a modified process without adhesive in the coil area, a 4.8 nH inductor achieves a peak Q-value of 30 at 1 GHz. High-Q 8 nH and 13.8 nH inductors have also been fabricated.