We report the results of studying the morphological structure of island systems formed by melting Sn, Bi and eutectic Sn-Bi polycrystalline films 2-70 nm thick deposited on carbon substrates. Substrate coverage with a film is found to be non-uniform against film mass thickness after its melting and crystallization. The interval of film thickness is determined where the island systems with narrow enough particle size distribution are formed under melting. (C) 2011 Elsevier B. V. All rights reserved.