Microstructure and electrical properties of Ag-MgF2 cermet films with high Ag content

摘要

An investigation has been made of the microstructure and the electrical properties of Ag-MgF2 cermet films, with a high Ag fraction, prepared by vacuum evaporation technique. The results show that the cermet film is composed of mainly amorphous MgF2 matrix with embedded fcc-Ag nanoparticles. The results also show that the sheet resistance of the Ag-MgF2 film varies between 200 and 2Omega/square within the composition range of 30-70wt% Ag-MgF2, that the percolation threshold occurs when Ag volume fraction reaches about 0.14, and that the TCR of the film is between 220 and 560 ppm/degreesC within the same film composition range. The positive TCR of the films with an Ag content of 30-70 wt% could be related to electrical conduction of a conducting network. (C) 2002 Elsevier Science Ltd. All rights reserved. [References: 11]