Pd/Ag thin film deposited on negative temperature coefficient (NTC) ceramics by direct current magnetron sputtering

Abstract

Metallization of Negative Temperature Coefficient (NTC) thermistors deposited via direct current magnetron sputtering had been the main subject of this extensive research. A variety of multi-layered thin films, namely Pd (35 nm–1200nm)/Ag(400 nm), were utilized as a multilayer structure electrode materials. On the other hand, a conventional screen printing silver paste electrode was used for a comparative study. In general, the Pd/Ag experimental results had shown that the electrode had a good ohmic contact with ceramics. The resistance of electrodes using Pd/Ag was constantly lower than that of using traditional screen-printed electrodes (29.9–33.7 < 34.1 kΩ). To elaborate, its tensile strength intensifies as the width of the transition layer (Pd) expanded. The tensile strength also reached its maximum at 7.17 MPa as the transition layer width extended up to 800 nm. In addition, it can be concluded from the SEM and EDS mapping image that the newly electrode prevented Ag from diffusing into the ceramic.