MEMS-based fabrication of high-performance inductors with back hollow structure and ferromagnetic film

The development of novel on-chip device techniques is attracting more and more interest because of the increasing demand for communication electronics, wearable devices and Internet of Things (loT) with features of low power consumption, high frequency-response, small size, fast transmission rate, and low-costs in the lab-on chip field. This letter presents the high frequency performance enhancement of on-chip inductors by the use of a back hollow structure filled with CoFeB/ZnO/CoFeB thin ferromagnetic layers. The magnetization dynamic response of this ferromagnetic stacks deposited by RF-magnetron sputtering were investigated. The inductance increases by 412%-70.6% between 0.1 and 8 GHz reaching 70.6% at 6.9 GHz. Q-factor increases also in a range of 3% to 18% between 0.1 and 3.8 GHz and reach 18% at 1.5 GHz. The equivalent circuit model and simplified physical model of the individual inductor were established and used to model and describe the parameters of inductor, such as the inductance and Q-factor as function of frequency. The results show the potential for application of the back hollow structure inductors with ferromagnetic thin film in RF circuits. (C) 2016 Published by Elsevier B.V.