Radical-Enhanced Atomic Layer Deposition of Metallic Copper Thin Films

Radical-enhanced atomic layer deposition (REALD) of metallic copper films from copper(II)acetylacetonate and hydrogen radicals was studied. For this work, a new kind of REALD reactor was developed by adding a surface-wale launcher type of microwave plasma source to an inert gas-valved flow-type ALD reactor. The copper films, grown at 14 deg C, were polycrystalline, exhibited low resistivity, 15 mOmega cm for a 25 nm thick film, and had relatively low impurity levels. The films had excellent adhesion, and they grew conformally. The successful incorporation of the radical source to the ALD reactor encourages the study of other challenging ALD processes.