Monday February 18 4:00 - 4:50 PM Kelley 1001
Donald S. Gardner Circuits Research Lab Intel Labs Hillsboro, OR Integrated On-Chip Inductors Using Magnetic Material The integration of on-chip inductors with magnetic materials in Si technology has been a major challenge in the move towards monolithic solutions for wireless microelectronics, power delivery, and EMI noise reduction. On-chip inductors with 2 levels of magnetic material have been integrated into advanced 90 nm and 120 nm CMOS process using Al and Cu metal and CoZrTa magnetic material. The magnetic material has to have high-temperature and long annealing-time stability, minimal hysteretic loss, high saturation magnetization, low magnetostriction, high resistivity, and compatibility with Si technology. CoZrTa has a saturation magnetization of 1.6 Tesla, a high permeability of 850, and low coercivity of 0.015 Oe. The CoZrTa increases the inductance and quality factors (ωL/Rac) by up to a factor of 27X, much higher than before. With such improvements, the effects of eddy currents, skin effect, and proximity effect become clearly visible. The ratios of L/R (inductance versus AC resistance) of different width lines using 5 um thick Cu or 1 um thick Al are shown with 2 layers of CoZrTa except as indicated. Diagonal lines indicate corresponding Q-factors. Using Cu and thicker CoZrTa increases the L/ Rac ratios, but eddy currents are limiting the Q-factor. Eddy currents are more severe with thicker magnetic films confirmed by simulations (see dashed lines). Adding slots or laminations reduces the eddy currents, but also reduces the inductance. Biography: Don Gardner has been with Intel Corporation since 1991 and is currently a principal engineer in the Circuits Research Lab and also is a visiting scientist at Stanford University. Don received his PhD in Engineering from Stanford University. He has had appointments as a visiting research scientist at Hitachi Research Labs located in Japan and as an instructor at Stanford University. He is the inventor or co-inventor of 54 patents including for inductors using high-frequency magnetic materials, Al-Ti layered metal for interconnections, reflow of copper metal, and embedded ground planes. Don has published and presented over 100 electrical engineering, materials science and computer science papers. He has received 3 Best Paper and Poster awards at international conferences and his paper on RF inductors was judged the best at the IEEE IITC conference. He enjoys bringing new life to old technologies by blending them with different technologies or recent science and materials. His current interests include magnetic materials for inductors, silicon-based optoelectronic devices, nanostructure design, and process technology.
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