The properties of thin films (0.03-2 mum) of high-density polyethylene spin-coated at elevated temperatures (100- 180 degreesC) onto silicon wafers and evaporated gold films were investigated. The coatings were characterized with respect to thickness (ellipsometry, QCM), chemical composition (ESCA, TOFSIMS), and morphology (optical microscopy, AFM). Initial deposition temperature was found to be an important process parameter that affected the crystal morphology, uniformity, and thickness of the films. The nucleation and the crystal growth were found to depend on both the substrate type and surface properties, especially at low supercooling. Below a film thickness of 0.1 mum, the morphology was composed of aggregates of edge-on oriented lamellae instead of the flattened spherulitic structure observed in thicker films. This thickness dependence of the morphology ceased when the spin-coating was performed at the lowest process temperature, since crystallization probably occurred in the presence of solvent, rather than via a polymer melt, which promoted spherulitic growth. Low process temperatures also gave more uniform films and suppressed the formation of surface striations owing to lower solvent evaporation rate.