Laser crystallisation during pulsed laser deposition of barium titanate thin films at low temperatures
| Autor: | B. Vosseler, Ernst Wolfgang Kreutz, Jens Gottmann |
|---|---|
| Přispěvatelé: | Publica |
| Rok vydání: | 2002 |
| Předmět: |
Materials science
Barium titanate medicine.medical_treatment Analytical chemistry General Physics and Astronomy laser crystallisation Substrate (electronics) Dielectric Pulsed laser deposition law.invention chemistry.chemical_compound symbols.namesake law medicine Thin film pulsed laser deposition Excimer laser Surfaces and Interfaces General Chemistry Condensed Matter Physics Laser Surfaces Coatings and Films chemistry in situ laser annealing symbols Raman spectroscopy |
| Zdroj: | Applied Surface Science. :831-838 |
| ISSN: | 0169-4332 |
| DOI: | 10.1016/s0169-4332(02)00457-9 |
| Popis: | Using a high dielectric material as substitute for SiOxNy in dielectric film capacitors of dynamic memories (DRAM) allows a significantly higher integration density and a reduction of the die size, even with planar capacitors. BaTiO3 is such a material. A dielectric constant of Epsilon r > 1000 has been achieved in thin films, made by pulsed laser deposition (PLD). For applications in microelectronic memories it is necessary to produce crystalline, defect-free and oriented BaTiO3 thin films at substrate temperatures, TS < 450 deg C. Sintered targets of BaTiO3 are ablated by KrF excimer laser radiation. The processing gas atmosphere consists of O2 at pressures of 0.1-50 Pa. The substrate is resitively heated to 360-440 deg C and annealed after or during PLD on Pt/Ti/Si multilayer substrates using KrF excimer laser radiation with fluences up to 120 mJ/cm2. The temperature distribution in the BaTiO3/Pt/Ti/Si multilayers during laser annealing is dynamically modelled and related to the resulting crystal quality and the dielectric properties of the films. With PLD a minimum substrate temperature of 500 deg C is necessary to deposit crystalline BaTiO3 films. Using in situ laser crystallisation crystalline BaTiO3 films can be deposited at substrate temperatures of TS = 360-440 deg C showing a dielectric constant of up to Epsilon r = 1200. The ferroelectric and dielectric properties of the films are determined by C-V and P-V impedance measurements and correlated to the chemical and structural properties, as determined by X-ray photoemission spectroscopy, X-ray diffraction, micro Raman spectroscopy and scanning electron microscopy. |
| Databáze: | OpenAIRE |
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