Eu and Tb3+ doped Y2O3, Y2SiO5 and Y3Al5O12(YAG) phosphor materials were prepared by different routes to investigate their effect on luminescent characteristics in micron and submicron particle size powders. Both amorphous low temperature co-precipitate reacted and crystalline high temperature solid state reacted (reference) powders were further crystallized in steam(S) and fluoriferous steam (SF) atmospheres at 1000(eta) C for 8 hours, respectively. In spite of sharp XRD peaks in S, SF treated samples, all SEM images exhibited "soft" aggregates of about 3 mu m in average diameter consisting of 0.2-0.3 mu m small particles. The powder samples characterized by XRD, SEM and luminescence spectra indicated that low temperature reacted samples which were further crystallized in steam or fluoriferous steam have greater improvements in the luminescent intensity than solid state reacted Y2O3, Y2SiO5 based phosphors after S, SF treatments.