We studied growth and characterization of $SrBi_2Ta_2O_9$ (SBT) thin films fabricated by low temperature process under vacuum and/or oxygen ambient. A metal organic decomposition (MOD) method based on a spin-on technique and annealing process using a rapid thermal annealing (RTA) method was used to prepare the SBT films. The crystallinity of a ferroelectric phase of SBT thin films is related to the oxygen partial pressure during RTA process. Under an oxygen partial pressure higher than 30 Torr, the crystallization temperature inducing the ferroelectric SBT phase can be lowered to $650^{circ}C$. Those films annealed at $650^{circ}C$ in vacuum and oxygen ambient showed good ferroelectric properties, that is, the memory window of 0.5~0.9 V at applied voltage of 3~7 V and the leakage current density of 1.80{ imes}10^{-8}$ A/$ extrm{cm}^2$ at an applied voltage of 5V. In comparison with the SBT thin films prepared at 80$0^{circ}C$ in $O_2$ ambient by furnace annealing process, the SBT thin films prepared at $650^{circ}C$ in vacuum and oxygen ambient using the RTA process showed a good crystallization and electrical properties which would be able to apply to the virtul device fabrication precess.