THE MICROSTRUCTURE OF THIN-FILMS OBSERVED USING ATOMIC-FORCE MICROSCOPY

Atomic force microscopy was used to study the microstructure and nanos tructure of sputtered and evaporated columnar thin films. The atomic f orce microscope was shown to be a useful tool for studying the surface topography of these technologically interesting surfaces. Two structu re zone transitions were studied: the substrate-temperature dependent, zone 2 to zone 3 transition and the sputter-pressure dependent zone 1 to T transition. Columns of zone 1 films were found to occur in a num ber of different shapes; rounded domed columns, elongated rounded colu mns, and faceted columns. The differences in the column shape are attr ibuted to differences in preferred growth directions and anisotropic a datom sticking coefficients. It was also found that the surfaces of th e columns also contained structure. The form of these structures varie d depending on the material. In many films, the surface of the columns was smooth, while in a few films the surface of the individual column s contained significant texture. For example, the surface of a TI-W th in film consisted of corrugations less than 10 Angstrom high. The corr ugations were between 100 and 200 Angstrom apart. Finally, the effect of the tip shape on the AFM images presented in this paper is discusse d.