The effects of in situ prepulse treatment on the bottom Pt electrode of a metal–insulator–metal (MIM) capacitor prior to atomic layer deposition process were investigated for the first time. The cross-sectional transmission electron microscopy (TEM) shows a thicker layer on the prepulsed Pt surface than that on the no-prepulsed Pt surface. According to TEM results and grazing incidence X-ray diffraction, it shows that the polycrystallization of the film with the predominant monoclinic phase can be suppressed when the bottom Pt electrode was pretreated by pulses. X-ray photoelectron spectroscopy indicated that the surface of the bottom Pt electrode was hydroxylated, which was considered to be able to facilitate metallorganic precursor bonding with –OH groups on the Pt surface. Atomic force microscopy reveals that the roughness on the film surface decreases with increasing prepulse cycles. Symmetrical leakage current density versus applied voltage curves were observed. Lower capacitance densities and reduced of the -prepulsed samples can be attributed to a thicker dielectric layer. A MIM capacitor has a capacitance density of , the quadratic voltage coefficient of capacitance of , and of at and at room temperature.