Dependence of the thickness profile of pulsed laser deposited bismuth films on process parameters

High resolution, two-dimensional thickness profiles of ArF excimer laser deposited Bi films are recorded by a microdensitometer, The azimuthal dependent cross-sectional profiles are consistently fitted by linear combinations of a cos4 Theta evaporation-like component and a much more sharply peaked one with exponents ranging from 8 to 61. When keeping the laser spot dimensions fixed, no dependence on laser fluence is obtained. An increase in Ar pressure from 10(-6) to 10(-1) Torr leads to the sharpening of the angular distribution along both axes: the forward directed component narrows from Cos(23)Theta to cos(61)Theta along the short, and from cos(9) Theta to cos(17)Theta along the long axis, respectively. Further increase in pressure results in a sudden broadening leading to circular symmetry at around 0.5 Torr. Above 10(-4) Ton: the deposition rate continuously decreases with increasing Ar pressure. In He atmosphere only narrowing is obtained above 10(-1) Torr.