Theory of conduction in ultrafast metal-insulator varistors

摘要

This paper investigates the fundamental operation of and mechanism of conduction occurring within metal-insulator varistors (MIVs). MIVs based on micron-sized spherical metal particles coated with nanometer-thick Al_2O_3, SiO_2, and BN films are investigated and discussed. MIV functionality is found to be dependent on the non-Ohmic operation of the thin electrically insulating films separating adjacent conductive metal particles within the high-density varistor particle matrix. Several experimental results suggest that the breakdown and conduction behavior are strongly dominated by Fowler-Nordheim tunneling and can be accurately modeled by a simple tunneling expression. The exceptional electrical properties exhibited by MIVs suggest a strong potential for use in the suppression of fast rise-time transients.