Characterization of physical and electrical properties of BaTiO3 films deposited on p-Si by modified polymeric precursors

Abstract

Highly uniform BaTiO 3 (BTO) films with thickness well below 100 nm were deposited on p-Si by spin coating using a modified polymeric precursor method. The polymeric precursor gel was redissolved into glacial acetic acid to improve the wetting property of the spinning solution to the Si substrates (2.5-in. diameter). The morphology, composition, thickness, and refractive index of the films were investigated using x-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS), and ellipsometry. The films are found to be polycrystalline. They exhibit uniformity over the whole wafer in regard to thickness, composition, and absence of surface features. The capacitors constructed with the BTO films on Si were further investigated by electrical characterizations. Current-voltage (I-V) measurements reveal a leakage current due to a Poole-Frenkel mechanism. The energy gap is evaluated to be 3.95 eV. A metal-insulator-semiconductor (MIS) behavior is observed through capacitance-conductance-voltage (C-G-V) measurements. The interface state density (D it ) at the BTO/p-Si interface is estimated to be of the order of 10 12 eV Ϫ1 cm Ϫ2 .

Leakage current analysis of hydrothermal BaTiO3 thin films

“…The activation energy agrees with that reported in the literature [10,19,20] but are much lower that those seen in relatively defect-free barium titanate (3.95 eV [21]) indicating that the defects in baked hydrothermal films, which are presumably oxygen vacancies or lattice hydroxyls, act as shallow traps and the trapping and detrapping results in easier conduction.…”

Control of Oxygen Vacancies in TiO6 Octahedra of Amorphous BaTiO3 Thin Films with Tunable Built‐In Electric Field in a‐BaTiO3/p‐Si Heterojunction for Metal–Oxide–Semiconductor Applications

“…This has motivated researchers to look for an alternative gate insulator with a larger dielectric constant. Among the contenders, perovskite BaTiO 3 (BTO), as a typical lead‐free displacement‐type ferroelectric featuring a large dielectric constant, stands out . Many researchers have investigated the functionalities of BTO thin film deposited on Si substrates, which not only can be used as a gate insulator, but also has other properties such as a rectifying effect, a photovoltaic effect, a room temperature luminescent effect, and an antireflection effect …”