Chemical Sputtering of Tungsten at Elevated Temperatures

Abstract

Positive ions emitted from heated tungsten filaments operating in various gas environments and in residual gases remaining at 10−11 Torr have been investigated. The ions appear both as a continuous current and in the form of ion bursts. The pressure and temperature dependence of the ion current is given; the properties of the bursts are investigated; and a model for the mechanism of burst production is proposed. It is shown that the ion current can be used as a sensitive indicator of surface reactions.