Record Q symmetrical inductors for 10-GHz LC-VCOs in 0.18-μm gate-length CMOS

We report a single-loop inductor suitable for integration in a differential voltage-controlled oscillator (LC-VCO) with 0.6-nH inductance and record quality factors of 18 at 10 GHz and 20 at 15 GHz fabricated in an industrial CMOS process on a 10 /spl Omega/cm substrate. A new lumped element model which accurately describes the inductor performance without the need for frequency-dependent elements is presented. During the course of this work, we found that a patterned ground shield significantly improves the inductor performance at these frequencies, but only when the polysilicon bars are connected from the center of the inductor.

[1]  K. O.,et al.  The effects of a ground shield on spiral inductors fabricated in a silicon bipolar technology , 2000, Proceedings of the 2000 BIPOLAR/BiCMOS Circuits and Technology Meeting (Cat. No.00CH37124).

[2]  R. J. Havens,et al.  Impact of probe configuration and calibration techniques on quality factor determination of on-wafer inductors for GHz applications , 2002, Proceedings of the 2002 International Conference on Microelectronic Test Structures, 2002. ICMTS 2002..

[3]  D. Edelstein,et al.  Monolithic spiral inductors fabricated using a VLSI Cu-damascene interconnect technology and low-loss substrates , 1996, International Electron Devices Meeting. Technical Digest.

[4]  R. J. Havens,et al.  A calibrated lumped-element de-embedding technique for on-wafer RF characterization of high-quality inductors and high-speed transistors , 2003 .

[5]  J.A.M. Geelen,et al.  An improved de-embedding technique for on-wafer high-frequency characterization , 1991, Proceedings of the 1991 Bipolar Circuits and Technology Meeting.

[6]  Domine M. W. Leenaerts,et al.  Design of wireless LAN circuits in RF-CMOS , 2002 .

[7]  D. Edelstein,et al.  RF circuit design aspects of spiral inductors on silicon , 1998, 1998 IEEE International Solid-State Circuits Conference. Digest of Technical Papers, ISSCC. First Edition (Cat. No.98CH36156).

[8]  L.F. Tiemeijer,et al.  Record Q spiral inductors in standard CMOS , 2001, International Electron Devices Meeting. Technical Digest (Cat. No.01CH37224).

[9]  J. Long,et al.  A Q-factor enhancement technique for MMIC inductors , 1998, 1998 IEEE MTT-S International Microwave Symposium Digest (Cat. No.98CH36192).