a method is provided for forming a conductive layer of ruthenium oxide layer ruo 2 . the ruo 2 layer is formed from a coating of a precursor solution comprising a ruthenium nitrosyl salt , subsequent heat treatment , and annealing at low temperature . the resulting layer of a tetragonal phase of crystalline ruthenium oxide is suitable for formation thereon of a perovskite structure ferroelectric material for applications in ferroelectric non - volatile memory cells . the chloride free process is compatible with processing for submicron device structures for bipolar , cmos or bipolar cmos integrated circuits .