Soft magnetic materials application in the RF range

Abstract Recent rapid progress of information technologies has enlarged the application fields of soft magnetic materials operating in GHz range. Firstly, this paper reviews the recent achievement of magnetic thin films applied in high-frequency devices. Then, a newly developed permeability measurement technique is introduced, and then ferromagnetic RF integrated inductors and noise suppressors are discussed from an application viewpoint. In particular, the influences of alignment between the patterned magnetic films and coil legs on the characteristics of inductors are manifested. As a result, a quality factor of 13 in a “shift type” inductor at 1.2 GHz was achieved.

[1]  Y. Shimada,et al.  Amorphous Co–metal films produced by sputtering , 1984 .

[2]  S. Couderc,et al.  Bidirectional ferromagnetic spiral inductors using single deposition , 2005, IEEE Transactions on Magnetics.

[3]  T. M. Crawford,et al.  Methods for determination of response times of magnetic head materials , 1999 .

[4]  N. Matsushita,et al.  Ni–Zn ferrite films with high permeability (μ′=∼30,μ″=∼30) at 1 GHz prepared at 90 °C , 2002 .

[5]  S. Ohnuma,et al.  Granular thin films with high RF permeability , 2003, Digest of INTERMAG 2003. International Magnetics Conference (Cat. No.03CH37401).

[6]  O. Acher,et al.  Cross measurements of thin-film permeability up to UHF range , 2002 .

[7]  Masahiro Yamaguchi,et al.  MICROFABRICATION AND CHARACTERISTICS OF MAGNETIC THIN-FILM INDUCTORS IN THE ULTRAHIGH FREQUENCY REGION , 1999 .

[8]  K. Arai,et al.  Sandwich type ferromagnetic RF integrated inductor , 2001, 2001 IEEE MTT-S International Microwave Sympsoium Digest (Cat. No.01CH37157).

[9]  Shigeyoshi Yoshida,et al.  High-frequency noise suppression in downsized circuits using magnetic granular films , 2001 .

[10]  Olivier Acher,et al.  An improved permeameter for thin film measurements up to 6 GHz , 1999 .

[11]  Masahiro Yamaguchi,et al.  A New 1 MHz-9 GHz Thin-Film Permeameter Using a Side-Open TEM Cell and a Planar Shielded-Loop Coil , 2003 .

[12]  Masahiro Yamaguchi,et al.  High Frequency Characteristics and Soft Magnetic Properties of FeCoBN Nanocrystalline Films , 2004 .

[13]  S. Ohnuma,et al.  Anisotropy Field and Electrical Resistivity in Magnetically Soft Co-Pd-Si-O Thin Films , 1999 .

[14]  Yutaka Shimada,et al.  Magnetic properties and frequency characteristics of (CoFeB)x-(Si01.9)i-x and CoFeB films for RF application , 2002 .

[15]  M. Yamaguchi,et al.  RF integrated noise suppressor using soft magnetic films , 2004, IEEE Transactions on Magnetics.

[16]  S. Yabukami,et al.  Sandwich films: Properties of a new soft magnetic material , 2000, Nature.