Annealing effects of Sn-Al and Sn-Cu nano thin films on mechanism of electromagnetic interference shielding

The sputtered Sn-Al and Sn-Cu thin films were used to investigate the effects of the crystallization mechanism and film thickness on the electromagnetic interference (EMI) characteristics. In addition, the annealed microstructure, electrical conductivities and EMI characteristics of the Sn-xAl films and the Sn-xCu films were compared. The results show that the electromagnetic interference (EMI) shielding of Sn-Al film was increased after annealing. For the Sn-Cu films with higher Cu mole concentration, the low frequency EMI shielding could not be improved. After annealing, the Sn-Cu thin film with lower Cu mole concentration possesses excellent EMI shielding at lower frequencies, but has an inverse tendency at higher frequencies.