1,720,969 research outputs found
Ti thickness effects in Pt/Ti bottom electrode on properties of (Ba,Sr)TiO3 thin film
No full textPt/Ti bilayers with various thicknesses of Ti adhesive layer were deposited in-situ by electron-beam evaporation on SiO2/Si substrates to investigate crystallinity, interdiffusion and surface morphology of Pt and overgrown BST films. It was found that the properties of Pt and BST films are strongly dependent on the thickness of a Ti layer, and the problems in Pt/Ti bilayer structure can be solved by using the Ti adhesive layer with the thickness range from 30 Angstrom to 50 Angstrom. Moreover, we could confirm the usefulness of Pt/Ti structure with suggested Ti thickness from the measurements of electrical properties such as dielectric constant and leakage current density
Platinum Bottom Electrode Formed by Electron Beam Evaporation for High Dielectric Thin Films
No full textA simple method for high-frequency characterization of (Ba,Sr)TiO3 thin film capacitors
No full textWe developed a simple method for characterizing high-frequency properties of (Ba,Sr)TiO3 thin film capacitors. This method includes a new fabrication process, a simple circuit model of measurement pattern and an easy procedure to de-embed parasitic components. In this study we successfully fabricated BST capacitors of Pt/ Ba0.7Sr0.3TiO3/Pt/Ti structure on the SiO2 coated Si substrate using a combination of lift-off process, wet etching and Au plating process. Also, we de-embedded parasitic components in the coplanar-type probing pad using two de-embedding patterns. As a result, it was found that the BST film had high dielectric property up to 5 GHz. This microwave property of the BST film is considered to be suitable for DRAM applications
Improvement of dielectric properties by inserting oxygen-rich initial layer in Pt/(Ba,Sr)TiO3/Pt structure
No full textBa0.7Sr0.3TiO3 thin films with thicknesses ranging from 330 Angstrom to 2200 Angstrom were deposited on Pt/SiO2/Si substrates by RF-sputtering. To improve the dielectric constant of BST film, we inserted oxygen-rich layer at the initial stage of BST film deposition, the thickness of which was varied to 60 Angstrom. As the thickness of the initial oxygen-rich layer increased, the dielectric constant of 1100 Angstrom -thick BST films increased rapidly. Based on two assumptions, the thickness of the interfacial layer of the BST film without the oxygen-rich layer was estimated to be less than 70 Angstrom and its dielectric constant to be less than 110. And, it was found that the dielectric constant of the interfacial low dielectric layer increased to 415 when 60 Angstrom -thick initial oxygen-rich layer was inserted
Fabrication and characterization of MFISFET using Al2O3 insulating layer for non-volatile memory
No full textMetal-ferroelectric-insulator-semiconductor (MFIS) structures including an Al2O3 insulator layer and a SET ferroelectric film are fabricated with their optimum thicknesses extracted by computer simulation, and then electrical properties of MFIS structures are investigated. In Pt/Al2O3/Si structure, no hysteresis and low leakage current of 7.5x10(-9)A/cm(2) have been observed. The MRS structure, Pt/SBT/Al2O3/Si, shows a memory window width of 1.2 V at an operation voltage of 5 V and a gate leakage current density of 7x10(-8)A/cm(2) at 1 V. Fatigue characteristics of the MFIS structure are also studied
Iridium thin film as a bottom electrode for high dielectric (Ba,Sr)TiO3 capacitors
No full textWe propose Ir thin films as new electrode materials for high dielectric BST capacitors. Ir was found to be superior to Pt in a number of aspects such as resistivity, adhesion and surface roughness. The Pt/BST/Ir/SiO2/Si capacitors showed leakage currents as low as Pt/PST/Pt/SiO2/Si ones, but higher capacitance resulted. For endurance properties with +5V unipolar pulse trains, the dielectric constant of BST films on Ir decreased by only 10% below its initial value after switching of 10(9) cycles while that on Pt degraded by 30% after 10(8) cycles. Ir bottom electrode effects on BST film properties were well explained by the formation of IrO2 phases on the surface of Ir electrodes
Reactive Ion Beam Etching of Ir Bottom Electrode for High Dielectric (Ba,Sr)TiO3 Capacitor Integration
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Hysteresis analysis in capacitance-voltage characteristics of Pt/(Ba,Sr)TiO3/Pt structures
No full textCapacitance-Voltage (C-V) characteristics of Pt/(Ba, Sr)TiO3/Pt MIM capacitor were investigated. Hysteresis observed in the C-V characteristics of BST films was analyzed. The dependence of the C-V characteristics on the sweeping direction of applied voltage indicates that the hysteresis is caused by the interface trap charge between the BST film and the Pt electrode. A new method was proposed to characterize the interface traps from the hysteresis of C-V characteristics of MIM capacitor. The trapped electron density near the lower interface of the BST thin films was constant (similar to 3 x 10(12) cm(-2)) for all the film thickness ranging from 500 Angstrom to 2000 Angstrom, which suggests that the hysteresis is not caused by the bulk property of the BST film bur caused by the interfacial property
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