A technology of smooth 15 - 50 nm thin Bi-film fabrication with the surface roughness of about 1 nm using two ultrahigh vacuum film growth methods, partially ionized beam deposition (PIBD) and molecular beam deposition (MBD), was developed. The dependence of film surface morphology on the key growth parameters, deposition rate, growth temperature, film thickness, and deposited particles energy was investigated by atomic force microscopy, and optimum growth conditions were determined. In the case of PIBD method, the accelerating voltage was found to influence the surface morphology most distinctly. The most uniform and smooth films with equal size grains and minimum roughness of 1 nm were grown at the accelerating voltage 3 - 4 kV. It was also found that bismuth films grown under the optimum condition 4 kV become continuous when the film thickness is more than 10 nm. In the case of MBD method, a decrease of the growth temperature down to 40°C substantially suppresses the growth of surface hillocks and the film surface roughness is reduced down to 1 nm. The obtained results can promote developing a nanotechnology for nanowire and quantum-well structure fabrication using thin semi-metallic Bi films.