Nano Science and Technology InstituteNano Science and Technology Institute
Nano Science and Technology Institute 2004 NSTI Nanotechnology Conference & Trade Show
Nanotech 2004
BioNano 2004
Program
Topics & Tracks
Sunday
Monday
Tuesday
Wednesday
Thursday
Index of Authors
Keynotes
Awards
Tutorials
Business & Investment
2004 Sub Sections
Sponsors
Exhibitors
Venue 2004
Proceedings
Organization
Press Room
Purchase CD/Proceedings
NSTI Events
Subscribe
Site Map
Nanotech Proceedings
Nanotechnology Proceedings
Supporting Organizations
Nanotech Supporting Organizations
Media Sponsors
Nanotech Media Sponsors
Event Contact
696 San Ramon Valley Blvd., Ste. 423
Danville, CA 94526
Ph: (925) 353-5004
Fx: (925) 886-8461
E-mail:
 
 

Integrated High Frequency RF Inductors with Nano/micro Patterned Ferromagnetic Cores

Y. Zhuang, M. Vroubel, B. Rejaei and J.N. Burghartz
Delft University of Technology, NL

Keywords: self-assembled, RF, granular, ferromagnetic, inductor

Abstract:
Integration of magnetic material has been long proposed to potentially improve performance and shrink size of on-chip inductive RF/microwave components, e.g. inductors, transformers, and transmission lines, which is crucial for the development of cost-effective RF/BiCMOS and RF/CMOS technologies [1]. Considerable efforts are underway to develop on-chip inductors with ferromagnetic cores having a high inductance per area (IPA) with a sufficiently high maximum quality factor (Qmax), a high operating frequency f(Qmax), and a high cut-off frequency (fcut-off) that is related to the ferromagnetic resonance (FMR) frequency [2]-[4]. However, the FM's high conductivity deteriorates the device performance at RF/Microwave frequencies manifested by the low Qmax, f(Qmax), and fcut-off, even the principal superior solenoid-type inductors have been exploited [4]. Reduction of the effective FM film conductivity and thus of eddy currents, while maintaining a sufficiently high permeability and FMR, can be achieved by nano/micro-size patterning of the FM film. Sophisticated multiple-target sputtering techniques have been proposed to deposit granular FM films [5]. In IC processing, a more cost-effective deposition method, such as electroplating, is certainly preferable, provided that nano/micro patterning is feasible. In this paper, we present a novel low-cost nano/micro structured Ni80Fe20 film that is deposited by electroplating in combination with an optimized seed layer. The superior magnetic properties of the Ni80Fe20 film at RF leads to a 3x higher Qmax and a 3x higher f(Qmax) compared to the state-of-the-art [4]. A record operating frequency f(Qmax) of >6.5 GHz and a record cut-off frequency (fcut-off) of >20 GHz are demonstrated. The configuration of a 4-turn nano/micro granular Ni80Fe20-core solenoid inductor is shown in Fig.1. Depositions of Ni80Fe20 films have been realized on three optimized types of seed layers, i.e. 100nm Ti (#a-seed), 100nm Ti covered by 10 nm TiN (#b-seed), and 100 nm Cr (#g-seed). During the electroplating deposition the FM films received the different nano/micro pattern illustrated in Fig.2. In contrast to the continuously plated homogeneous film (Fig.3c; #g- seed), a nano /micro structured film resulted from the #b- seed (Fig.2b), and the #a- seed gave a nano/micro pattern of mostly disconnected FM islands (R < 1.6 mm) (Fig.2a). Inductors having a #a-core clearly exhibited a higher FMR frequency and lower eddy current loss than inductors based on the #b-core or #g-core (Fig.3). The overall more than 3x enhancements of both Qmax and f(Qmax) have been achieved from the #a-core over the #g- core devices published by us at the past IEDM [4]. Inductance and quality factor versus frequency of three 4-turn #a-core inductors are shown in Fig.4 to have fcut-off >20 GHz. After systematically optimizing the design, the inductors with IPA>0.20 ìH/mm2, Qmax>4.5 and f(Qmax)>6.5 GHz have been achieved (Fig.5).

Nanotech 2004 Conference Technical Program Abstract

 
Sponsors
Nanotech Sponsors
News Headlines
NSTI Online Community
 
 

© Nano Science and Technology Institute, all rights reserved.
Terms of use | Privacy policy | Contact