ELECTRICALLY-INDUCED THERMAL TRANSIENT EXPERIMENTS FOR THERMAL-DIFFUSIVITY MEASUREMENTS ON CHEMICAL-VAPOR-DEPOSITED DIAMOND FILMS

To investigate the in plane thermal diffusivity of chemical vapor depo sited diamond layers, two new techniques were developed based on elect rically induced converging and linear thermal waves. With these method s, free-standing, laser-cut diamond samples, 100 mu m or larger in thi ckness can be analyzed. Laser cutting leaves a graphitic surface layer along the cutting edge. Therefore, a short high voltage pulse, applie d at the graphitic rim resistor, is used to generate a thermal transie nt. The propagation of the wave is measured optically either in the ce nter of the circular disk or at one side of a bar shaped sample. Both techniques require only very little sample preparation. They are shown to be simple, accurate, and independent of sample thickness and induc ed energy. In order to analyze the experimental data we present both a n analytical model and a numerical simulation. (C) 1998 American Insti tute of Physics.