High performance micro-machined inductors on CMOS substrate

Using a combination of micromachining and three-dimensional (3-D) processing technologies, we have designed, fabricated, and tested inductors on CMOS grade Si substrate (10∼20 Ω-cm resistivity) which exhibit very high quality factor and high resonant frequency. A 1.2 nH inductor in this process achieves a record high quality factor of ∼140 at 12GHz, with Q > 100 for frequencies between 8 to 20GHz. The technology to fabricate these inductors is based on one step deposition and electroplating of a stressed layered metal combination of Cr and Au and is fully compatible with CMOS technology.