We have successfully obtained a highly c-axis oriented epitaxial Pb(Zr, Ti)O3 (PZT) based thin film, 0.06Pb(Mn1/3, Nb2/3)O3-0.94Pb(Zr0.5, Ti0.5)O3 (PMnN-PZT), on a (100) Si substrate by fast cooling of the substrate just after sputter deposition. The Si substrates were covered with SrRuO3//La0.5Sr0.5CoO3//CeO2//yttria-stabilized zirconia buffer layers. It is found that c-axis orientation ratio of the PMnN-PZT thin film has reached more than 75% owing to the fast cooling (∼-180°C/min) although a-axis orientation is normally predominant on a Si substrate in a conventional sputtering process. A piezoelectric unimorph microcantilever utilizing the PMnN-PZT thin film was fabricated for characterizing the dielectric and piezoelectric properties. No damage was observed after the microfabrication process. As a result, 1∼4-μm-thick PMnN-PZT thin films exhibited a piezoelectric coefficient as large as e31,f = ∼-14 C/m2 with a small dielectric constant of εr = ∼270. These unique properties can provide an excellent figure of merit, (e31,f)2/ε0εr = ∼80 GPa, for piezoelectric microelectro-mechanical systems (MEMS) sensors such as piezoelectric gyroscope. The present piezoelectric thin films are expected to be used for a variety of high-performance piezoelectric MEMS devices.