Thin-film topography control with transient liquid underlayer

Abstract

A novel and effective technique for fabricating metal surfaces with controlled topography is described. The metal of interest is deposited onto a thin (25–200 A) underlayer of a liquid metal. Transient liquid reactions during film growth and coalescence lead to characteristic roughening of the deposits. Studies of 1-μm A1 films deposited on thin Ga underlayers revealed a consistent increase of the size of A1 features with the average thickness of the Ga underlayer. No apparent change in the films’ resistivity was detected. Limited studies of 1-μm Cu films with a Ga underlayer suggest the general applicability of this technique. © 1989, American Vacuum Society. All rights reserved.