Temperature effects in the photolytic LCVD of platinum

The photolytic laser chem. vapor deposition (LCVD) rate of Pt from its hexafluoroacetylacetonate complex precursor was measured in situ and in real time. Optical transmission of the 350 nm photolysis light through the deposited Pt film and a transparent glass substrate is monitored and analyzed in detail. From these measurements, as well as measurements of the reflected light, the fraction of the laser beam power adsorbed in the metal film is found. The latter allows a simple est. of the laser-induced temp. rise at the metal surface. Even small temp. increases can completely change the photolysis mechanism and hence drastically influence the photolytic LCVD rate. A simple modification of Lax's model, in which a temp.-dependent thermal cond. of the substrate is introduced, is used to describe the laser-induced heating of a strongly-absorbing thin metal film on a glass substrate.