Preferentially (105)-oriented SrxBi2+yTa2O9 (SBT) thin films on Pt, SiO2/n-Si and SiNx/SiO2/n-Si have been prepared at low temperature in O-2 by pulsed laser deposition. Excess Bi promotes crystallization of the film. The crystalline films have been obtained on Pt and SiO2/Si even at 350 degrees C, which is the lowest process temperature for growing SET ferroelectric thin films. Metal-ferroelectric-insulator-semiconductor (MRS) structure, which is very important in ferroelectric gate memory FET, has been fabricated by depositing the SET film on insulator-silicon, The MFIS structures show C-V hysteresis corresponding to ferroelectric hysteresis. Memory windows of the C-V hysteresis are 4.3 V in the SBT/SiO2/Si and 2.5 V in the SBT/SiNx/SiO2/Si. The memory window and fatigue property of the C-V characteristics are improved with decrease of the deposition temperature and the excess Pi content, Little degradations are induced in the C-V characteristics of SiNx/SiO2/n-Si structure when depositing the SET film by PLD at low temperature.