ABSTRACTReactive sputter deposition is a widely-used process for growing films of high melting point materials near room temperature and desirable metastable structures not attainable in material grown under conditions of thermodynamic equilibrium. Both categories include wide band-gap metal oxides. A first step towards reproducible growth is to develop a “phase map” for the metal-oxygen system of interest. The map graphically relates independent sputter deposition process parameters, the growth environment, and the metallurgical phase(s) formed in the film. This paper shows how phase maps are constructed and used to observe general trends in oxide phase formation sequence, with examples from the Nb-O, Y-O, and Zr-O systems.