Integrated Magnetic Nanoinductors

This paper demonstrates the feasibility of the realization of on-chip inductors for use in microwave and millimeter-wave devices using ultraminiaturized on-chip vertical nanohelices. The inductors are constructed by depositing a thin film of closely packed, vertically aligned Nickel nanohelices. The film is fabricated using a CMOS-compatible glancing angle physical vapor deposition method. The resulting nanostructured inductors are characterized from 10 to 70 GHz and are found to have inductances of 6 pH/μm², 60 times larger than conventional on-chip planar spiral inductors. A quality factor of three is measured and the results indicate that it continues to improve above 70 GHz, while inductance values remain relatively constant. The proposed nanostructured inductors can significantly reduce the chip area, and consequently the cost, of radio frequency and millimeter-wave integrated circuits. In addition, the nanostructured inductors offer significantly larger operation bandwidth than on-chip planar structures operating at frequencies above 100 GHz.