High-Q On-Chip C-Band Inductor With a Nanocrystalline MnZn-Ferrite Film Core

Ranajit Sai, R. D. Ralandinliu Kahmei, S. A. Shivashankar, Masahiro Yamaguchi

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


The miniaturized on-chip inductor was developed for the C-band (4-8 GHz) and beyond, to meet the requirements of upcoming 5G technology devices. This paper presents the deposition of nanocrystalline manganese-zinc ferrite (MnxZn1-xFe2O4; x = 0.5) thin films in a CMOS-compatible way on top of an on-chip inductor structure. A 200 nm-thick film was conformally deposited directly on a foundry-fabricated inductor after removing the top passivation layer by dry etching. The Q-factor is found to be enhanced by 10% at the upper end (8 GHz) of the C-band, while the self-resonance frequency of the inductor is up-shifted to 21 from 16 GHz. The film on a dummy Si (100) substrate exhibits saturation magnetization (4π MS= 160 mT) and coercivity (HC= 3.5 mT) much lower than for the bulk material. The film was deposited by a rapid (<5 min) and low-temperature (<200 °C) solution-based process under microwave irradiation (2.45 GHz) of 300 W. This is the first report of an on-chip C-band inductor with a manganese-zinc ferrite film core.

Original languageEnglish
Article number8742802
JournalIEEE Transactions on Magnetics
Issue number7
Publication statusPublished - 2019 Jul


  • C-band
  • Q-factor
  • inductor
  • manganese-zinc ferrite

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


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