Boron nitride films were prepared by pulsed laser ablation from a boron nitride target using a KrF-excimer laser, where the growing films were deposited in nitrogen atmosphere or bombarded by a nitrogen/argon ion beam. Films deposited at high growth rates or weak ion bombardment are hexagonal with turbostratic microstructure (called here 1-BN) and show high adhesive strength to silicon and stainless steel substrates. By using them as intermediate layers, the adhesion of pure cubic boron nitride films (c-BN) can significantly be improved. 1-BN films and 1-BN/h-BN/c-BN layer systems have been investigated by in situ ellipsometry and cross-section transmission electron microscopy. The mechanical properties, i.e. stress and hardness, of those films and layer systems are presented. 1-BN films deposited at high laser energy densities may have compressive stresses as high as 16 GPa. Their Vickers microhardness is in the range of 25-5.4 GPa depending on substrate temperature and ion bombardment. The compressive stresses of 400 nm thick adherent c-BN films were estimated to be 4.5 GPa.