Fabrication and Electrical Characterization of Pt/(Ba,Sr)TiO₃/Pt Capacitors for Ultralarge-Scale Integrated Dynamic Random Access Memory Applications

Abstract

Pt/(Ba, Sr)TiO3/Pt capacitors are fabricated using DC and RF magnetron sputtering processes on thermally oxidized silicon wafers for ultralarge scale integrated dynamic random access memory (ULSI DRAM) applications. (Ba,Sr)TiO3 (BST) thin film deposited at 640°C to 20 nm thickness shows an equivalent SiO2 thickness (t oxeq) of 0.35 nm and a leakage current density, measured at an applied voltage of 1.5 V, of about 100 nA/cm2. t oxeq of the BST film and leakage current density are further decreased to 0.24 nm and 40 nA/cm2, respectively, by postannealing at 750°C after fabrication of the top electrode.

Atomic Layer Deposition of SrTiO3 Thin Films with Highly Enhanced Growth Rate for Ultrahigh Density Capacitors

“…For these requirements, SrTiO 3 (STO) thin films must be the ultimate material of choice to overcome the limitations of the current ZrO 2 -based dielectrics , as well as the newly highlighted Al-doped TiO 2 , because it has a dielectric constant >100 even at a low film thickness (∼ 10 nm). Because physical − and chemical vapor deposition (CVD) methods − cannot meet the stringent conformality, atomic layer deposition (ALD) has been highlighted. − ALD, which is characterized by its unique self-limiting deposition mechanism, can be used to grow dielectric films as well as metal electrodes on account of its excellent conformal step coverage over the severe three-dimensional (3D) structure with a high aspect ratio in DRAM capacitors.…”

Impedance spectroscopic and dielectric analysis of Ba0.7Sr0.3TiO3 thin films

“…Barium titanate (BaTiO 3 ) and strontium titanate (SrTiO 3 ), usually named BST, attracted the researchers because of their high dielectric constant at room temperature and their potential in applications such as dielectric for dynamic random access memory (DRAMs), frequency-agile filters, voltage-controlled oscillators, phase shifters and antennas [2,3]. Majority of the perovskites such as BST, NST and BNA [2,[4][5][6][7][8] presents a significant dielectric relaxation and this phenomenon affects the electrical properties of the capacitors made with these dielectrics.…”

Effects of substrate temperature on the physical properties of strained BaTiO3/LaNiO3 artificial superlattices

“…For these methods, a high temperature ($650 1C) is necessary to obtain epitaxial superlattice films of high quality [5][6][7][8][9][10]. Sputtering is one of the most important methods for epitaxial perovskite oxide film deposition due to high reproducibility in the chemical composition and easy process control [11]. However, radio-frequency (RF) magnetron sputtering deposition has not yet been well established in the growth of high quality of an epitaxial oxide superlattice film.…”