Influence of filament geometry on film uniformity in a catalytic CVD system for low-temperature processing

The influence of the filament configuration in a low-temperature catalytic chemical vapor deposition system on the substrate temperature and thickness uniformity was investigated for application to the silicon-based thin-film transistor backplane on flexible substrates. Serial and parallel arrangements of the filament were attempted. In the serial connection, the self-heating of the substrate was suppressed as the total length of the filament decreased for a given filament temperature. The areal distribution of the film thickness was affected more by the shape of the reactor than by the filament arrangement, whereas the variation of the breakdown field strength and resistivity showed little correlation with the filament of the chamber geometry. On the contrary, in the parallel connection, the thickness distribution was influenced more by the location of the filaments than by the reactor shape. The 56 mm interfilament spacing resulted in the highest deposition rate, and the film thickness decreased radially from the center. When the interfilament spacing was 88 mm, both the average and the standard deviations of the thickness decreased, and the distribution changed, assuming an elliptical symmetry.