The formation of imperfections in epitaxial gold films

Abstract

Single crystal films of gold have been prepared by evaporation onto molybdenum disulphide inside an electron microscope. This technique has allowed direct and continuous observation, mainly by means of moir5 patterns, of the formation of lattice imperfections during film growth. It is shown that dislocations arise mainly from the rotation and displacement misfits between neighbouring islands of the deposit film, and that stacking faults and microtwins are formed at the junction plane between some of the coalescing islands. An analysis of these effects is given. One of the most significant results is that there is considerable annihilation and re-arrangement of the lattice imperfections during filni growth, particularly up to the stage of formation of a continuous hole-free film. The initial nuclei of the deposits are doubly positioned, and pronounced changes in orientation occur during and immediately following the coalescence of islands in different positions. This process occurs by the migration of double-positioning boundaries, and is interpreted in terms of conventional recrystallization theory.