Principles of Fluorine Distribution in Chemical Vapor Deposited Tungsten Films

The fluorine distribution in chemical vapor deposited tungsten films were studied. Tungsten was deposited on silicon and silicon dioxide substrates using both thermal‐activated and laser‐assisted chemical vapor deposition. It was found that the total amount of fluorine and its distribution could be described as a sum of three terms. The first term represents the fluorine accumulated in the tungsten/substrate interfacial region. These amounts were and when tungsten was deposited on silicon and silicon dioxide, respectively. The second term corresponds to a fluorine surface density of about at the tungsten surface. The third term originates from the bulk of the tungsten film where the fluorine concentration showed an Arrhenius dependence. The activation energy and the pre‐exponential factor were approximately and 10 15 atom/cm 3 , respectively. The negative sign on the activation energy means that the amount of codeposited fluorine decreases with increasing deposition temperature.