SCALING ANALYSIS OF CHEMICAL-VAPOR-DEPOSITED TUNGSTEN FILMS BY ATOMIC-FORCE MICROSCOPY

We have studied the static surface roughness of 500-nm-thick tungsten chemical-vapor-deposited polycrystalline films on length scales between 5 and 5 x 10(4) nm, using atomic force microscopy. The interface width scales as a power of the system size for small system sizes (< 1000 nm) but is constant for large sizes, which is in agreement with nonequilibrium interface growth theory. The scaling exponent (0.75 +/- 0.05) for short-length scales appears to be consistent with the recent prediction based on a conservative volume growth model. In the long-range regime, the rms value becomes larger as the substrate temperature is lowered.