The structure and current-voltage characteristics of copper-tungsten electric contacts prepared using a Plasma Focus installation

Abstract

The structure and current-voltage characteristics (CVCs) of copper-tungsten electric contacts deposited using a Plasma Focus facility are studied. It is shown that the reduced contact resistance is ∼0.4 × 10−6 Ω cm2 at 300 K and ∼0.4 × 10−7 Ω cm2 at 80 K, which meets the highest requirements for ohmic contacts in electrical installations and semiconductor electronics. The formation of microcracks on the surface of tungsten exposed to high-speed plasma streams has no significant impact on the contact resistance. Under the effect of high pressure, a melt of copper penetrates deep into tungsten along the cracks, solidifies, and thereby forms zones of high conductivity. The soldering of electric contacts with tin solder leads to CVC deviation from linearity at 80 K. A probable cause of this is the formation of SnO2-copper Schottky barriers on the surface of Cu-W contacts.