Figure 4. Development of voltage across the film/substrate interface.

The voltage drop measured between the film surface and the back surface of the substrate at four positions on a sample when an in-plane current of 5 × 10⁻⁵ Amps is imposed between electrodes 1 and 7 (see Fig. 1 for electrode configuration). The legend denotes the pairs of top/bottom electrodes used for each measurement. Measurements were taken at 370 °C, with the sample equilibrated at pO₂=1.5 torr.