Polycrystalline nickel lines as small as 1 &mgr;m in width were deposited by pyrolysis of nickel tetracarbonyl [Ni(CO)4] on polysilicon/silicon dioxide/monosilicon substrates. As heat source, a cw argon‐ion laser operating at several wavelengths around 0.5 &mgr;m was used. The growth kinetics, morphology, and electrical resistivity of the nickel microstructures were investigated at various scanning speeds of the laser spot, laser beam powers, and reactant gas pressures. From the deposition kinetics, the vertical deposition rate of nickel was calculated. For Ni(CO)4pressures below 0.3 mbar, deposition of flat‐topped nickel lines occurs. The deposition rate was proportional to the Ni(CO)4pressure and independent of the laser output power. For Ni(CO)4pressures above 0.3 mbar, lines with a Gaussian profile are obtained. The deposition rate was found to be independent of the Ni(CO)4pressure and exhibits an activation energy of 11.5 kcal mol−1. The measured electrical resistivity of the flat‐topped lines was about ten times higher than that of the bulk (7 &mgr;&OHgr; cm) while for the Gaussian lines this ratio falls below 1.5. Kinetic measurements with carbon monoxide (CO) as buffer gas were also performed. The nickel deposition rate was found to decrease as the CO partial pressure increases for all the Ni(CO)4partial pressures considered (0.2–20 mbar). The morphology and roughness of the deposited lines were investigated using both a scanning electron microscope and an atomic force microscope. The effect of the laser beam on the quality of the interfaces underlying the deposited lines was investigated by means of a focused ion beam system. On the basis of the experimental results, a decomposition mechanism of the Ni(CO)4molecules was elaborated.