THE INFLUENCE OF ARGON PRESSURE ON THE STRUCTURE OF SPUTTERED MOLYBDENUM - FROM POROUS AMORPHOUS TO A NEW-TYPE OF HIGHLY TEXTURED FILM

The density of the low-rate (<0.1 nm/s) sputtered molybdenum films can be controlled between 48% and 96% of the bulk material by the variati on of argon pressure from 4.7 to 0.45 Pa. Small angle x-ray scattering shows the existence of columnar voids with a typical size of 10 nm, e specially in the low-density films, whereas a high concentration of pr imary voids with a diameter of I nm is found independent of the densit y. The conductivity of the films decreases monotonically with decreasi ng density from 2.4x10(4) to 2.1x10(2) (Omega cm)(-1), with a strong d ecay below a density of 55%. Films of about 30 nm thickness are amorph ous or nanocrystalline with a (110) texture for high- and low-pressure sputter deposition, respectively. Upon increasing the film thickness up to 3 mu m, the low-density films become nanocrystalline, too, and d evelop the common (110) fiber texture. In contrast, increasing the thi ckness of the high-density films results in a turnover of texture from a (110) type to a (211) mosaiclike texture. (C) 1996 American Institu te of Physics.