Laser-pulse technique for measuring the thermal diffusivity of substrate-supported polymer films

We describe a technique for measuring the thermal diffusivity of substrate- supported polymer films based on the early-time electrothermal response fol lowing a 100 ns pulse from a Q-switched ruby laser. Data for a polyimide fi lm spin coated on a p-doped Si[111] substrate are used to demonstrate the t echnique. From the late-time decay of the signal, we also obtain an estimat e of the interfacial thermal-transport coefficient of the polymer-semicondu ctor interface. (C) 1999 American Institute of Physics. [S0034-6748(99)0411 1-8].