CMOS-compatible on-chip self-rolled-up inductors for RF/mm-wave applications

Wen Huang, Jingchao Zhou, Paul Froeter, Kathy Walsh, Siyu Liu, Julian Michaels, Moyang Li, Songbin Gong, Xiuling Li

Research output: Chapter in Book/Report/Conference proceedingConference contribution


On-chip copper (Cu) based self-rolled-up membrane (S-RuM) inductors are demonstrated for the first time. Compared to the gold (Au) based S-RuM inductor, device structures and fabrication processes are re-designed to realize CMOS compatibility by switching conduction metal to Cu and overcoming related processing challenges. Performance enhancements include ∼44% reduction of conduction layer resistivity compared to Au-based with the same thickness, and a clear path to 100% fabrication yield are achieved. RF measurement shows as high as ∼ 61nH/mm2 inductance density with just a 2-turn structure for these air-core S-RuM inductors. The achieved inductance is in the range from 0.3nH to 1nH. The best self-resonant-frequency (SRF) and quality factor (Q factor) of 1nH device is ∼23GHz and ∼2.4@5GHz, respectively. Much better performance can be readily obtained by rolling up more turns and integrating soft magnetic material thin film and core. Results show that Cu S-RuM inductor is very promising to replace on-chip planar inductor with better performance as a new industry standard.

Original languageEnglish (US)
Title of host publication2017 IEEE MTT-S International Microwave Symposium, IMS 2017
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages4
ISBN (Electronic)9781509063604
StatePublished - Oct 4 2017
Event2017 IEEE MTT-S International Microwave Symposium, IMS 2017 - Honololu, United States
Duration: Jun 4 2017Jun 9 2017

Publication series

NameIEEE MTT-S International Microwave Symposium Digest
ISSN (Print)0149-645X


Other2017 IEEE MTT-S International Microwave Symposium, IMS 2017
Country/TerritoryUnited States


  • CMOS compatible
  • Copper
  • High fabrication yield
  • Inductor
  • RF/mm-Wave frequency
  • Self-rolled-up

ASJC Scopus subject areas

  • Radiation
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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