A novel NiZn ferrite integrated magnetic solenoid inductor with a high quality factor at 0.7–6 GHz

Xinjun Wang,Nian X Sun,Yuan Gao,Brandon M Howe,Hwaider Lin,Xiaoling Shi,John G Jones,Huaihao Chen,Gail J Brown

doi:10.1063/1.4973283

Abstract

Integrated inductor is one of the fundamental components and has been widely used in radio frequency integrated circuits (RFICs). It has been challenging to achieve simultaneously high inductance and quality factor, particularly at GHz frequencies. In this work, we reported a novel integrated solenoid inductor with a magnetic NiZn ferrite as the core material, which was deposited by a low-cost spin spray technique. These integrated inductors showed a significant improvement in both inductance and quality factor at GHz frequencies over their air core counterparts. A stable inductance was observed within a wide frequency ranged from 700 MHz to 6 GHz. The peak value of quality factor reached 23, a relatively higher value not reported for solenoid inductors up to date. Our results indicate that the integrated inductor are promising for applications in RFICs.

Highlights

Integrated inductors with a high quality factor (Q-factor) have attracted more and more interests for radio frequency (RF) applications, especially for wireless communications in smart phones, tablet computers and wearable electronics etc
056606-3 Wang et al The M-H loops of NiZn ferrite films have been examined by vibrating sample magnetometer (VSM), represented by Fig. 2(a)
Solenoid inductors were fabricated by using spin sprayed NiZn ferrites as magnetic cores

Summary

INTRODUCTION

Integrated inductors with a high quality factor (Q-factor) have attracted more and more interests for radio frequency (RF) applications, especially for wireless communications in smart phones, tablet computers and wearable electronics etc. In previous works, increased inductance density and quality factor have been achieved by using sputtered or electroplated magnetic materials as an inductor core.[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21] For instance, by using Veeco-CVC system to deposit Co-Zr-Ta as a single-layer magnetic material in spiral inductors, Gardner et al.[1] reported an increase in inductance (30%–60%) at a frequency up to 3GHz. Gao et al.[19] demonstrated a high quality factor integrated RF magnetic inductors based on a solenoid structure with magnetic FeGaB/Al2O3 multilayers. The film was firstly deposited by the spin spray technique and applied as the magnetic cores of inductors

EXPERIMENT

RESULTS AND DISCUSSION

CONCLUSION