We have proposed the use of RMnO3 (R: rare earth elements) films for metal–ferroelectric–semiconductor field effect transistor (MFSFET)-type ferroelectric random access memories (ferroelectric RAMs). This reports the production of YMnO3 films on Si substrates for MFSFET with confirmation of the distinct ferroelectricity by P–E hysteresis and capacitance–voltage (C–V) measurement. (0001)-oriented YMnO3 films were obtained on a (111)Si substrate using a pulsed-laser deposition method. Although the Pt/YMnO3/Si structure exhibits a very small remnant polarization of 1.2 nC/cm2, it has clear ferroelectric polarization switching type C–V characteristics with a memory window of 1.1 V. The dielectric constant and the dissipation factor were 27.8 and 0.035, respectively. The polarization switching characteristics are discussed.