Multilayered Cu/NiFe thin films for electromagnetic interference shielding at high frequency

Cu/NiFe multilayers with different structures were fabricated by electroplating for electromagnetic wave interference shielding in the high-frequency region. The electromagnetic wave interference shielding effectiveness of the symmetric, asymmetric, and thickness-gradient multilayer films was evaluated to optimize these structures. The thickness of the NiFe layer, which acts as an interlayer between Cu layers, is an important factor. The five-layered thin film (S9), with a thickness gradient that continues to increase toward the lower layer, shows an electromagnetic interference shielding effectiveness of - 74 dB in the wideband region, even though the total thickness of the multilayer is 1 mu m. Focused ion beam, scanning electron microscopy, vector network, X-ray diffraction, four-point probe, and inductively coupled plasma-optical emission spectroscopy analyses were performed to characterize the multilayered Cu/NiFe thin films. (c) 2022 Elsevier B.V. All rights reserved.