Vacuum arc deposition has been used to grow thin, ultrahard carbon fil
ms. Multilayer structures consisting of four alternating double layers
of carbon with sp(3) contents of 80 and 40%, respectively, were grown
using a pulse bias technique for ion energy control. The relative pro
portion of the soft layer (40% sp(3) content) in the multilayer struct
ure was varied from 10 to 90%. The hardness of the multilayer structur
e is a weighted average of the hardnesses of the component layers. The
overall compressive growth stress is less than would be expected from
the proportions of the layer components. Pin-on-disk wear testing sho
wed that multilayer films have a lower wear rate than monolithic films
especially at higher loads. The lowest wear rate was measured in a fi
lm with alternating layers of approximately equal thicknesses of the h
ard and soft layers.