Abstract This paper demonstrates the growth of tantalum pentoxide (Ta 2O 5) on a silicon (Si) substrate at room temperature (∼10 °C) by means of a liquid phase deposition (LPD) method. Good quality and reliability is obtained due to the low temperature process. The deposition rate is up to 136.5 nm/h and the refractive index of the LPD-Ta 2O 5/Si is about 1.86 after annealing at 400 °C. The LPD-Ta 2O 5 film produced on the Si substrate is used to fabricate a metal–oxide–semiconductor (MOS) capacitor with a device area of 0.3 cm 2, giving a surface charge density of about 1.6×10 11 cm −2 and a breakdown voltage of 6.5 MV/cm. Also presented is a proposed mechanism for the LPD deposition of Ta 2O 5 on Si.