Etching characteristics of LaNiO 3 thin films in BCl 3 / Ar gas chemistry (original) (raw)
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Dry etching of LaNiO3 thin films using inductively coupled plasma
Thin Solid Films, 2006
The etching characteristics of LaNiO 3 (LNO) thin films and SiO 2 in Cl 2 /Ar plasma were investigated. LNO etch rates decreased with increasing Cl 2 fraction in Ar plasma and the working pressure. Langmuir probe measurement showed a noticeable influence of Cl 2 /Ar mixing ratio on electron temperature, electron density, and ion current density. The modeling of volume kinetics for charged particles and OES measurements for neutral atoms indicated monotonous changes of both densities and fluxes of active species such as chlorine atoms and positive ions. The LNO etch rate behavior may be explained by physical mechanisms.
New Physics: Sae Mulli, 2016
In this study, LaNiO3 (LNO) thin films are grown on SrTiO3 (STO) via pulsed laser deposition (PLD), and the influence of varying the laser energy density and the oxygen partial pressure on the microstructures and electrical properties is investigated. The LNO films are fabricated at a substrate temperature of 750 • C, and the energy densities and oxygen partial pressures are varied from 1.0 to 2.0 J/cm 2 and from 0.1 to 0.5 Torr, respectively. The crystallinity, surface morphology, and electrical properties of the LNO films are characterized by using high-resolution X-ray diffraction (HRXRD), atomic force microscopy (AFM), and electrical resistivity measurements. The LNO films are shown to be c-axis oriented and to have root-mean-squared surface roughnesses of 0.881, 0.743, and 0.603 nm for energy densities of 1.0, 1.5, and 2.0 J/cm 2 , respectively. The transport measurement indicates that LNO is a good metallic-oxide material.
Coatings
Precision control of resistivity/conductivity of LaNiO3 (LNO) films is essential for their integration as electrodes in the functional heterostructures. This becomes possible if the relationship between processing parameters–composition–structure–resistivity is determined. LaNiO3 films were deposited by three different chemical vapor deposition methods using different precursor supply systems: direct liquid delivery, pulsed liquid injection, and aerosol generation. The possibilities to ameliorate the efficiency of precursor evaporation and of film growth were studied. The relationship between deposition conditions and composition was determined. Detailed analysis of the epitaxial growth of LNO films on cubic and trigonal substrates and the influence of the rhombohedral distortion on the microstructural quality was done. The resistivity of LaNiO3 films, grown by chemical vapor deposition, was mainly defined by microstructural defects and La/Ni composition. The high epitaxial quality ...
Nanoscale etching of perovskite oxides for field effect transistor applications
Journal of Vacuum Science & Technology B, 2020
The etching of epitaxially grown perovskite oxide BaSnO 3 (BSO) and BaTiO 3 (BTO) thin films is studied using Cl-based (BCl 3 /Ar) and F-based (CF 4 /Ar) plasma chemistries in an inductively coupled plasma reactive ion etching (ICP-RIE) system for development of field effect transistors. It is found that the BCl 3 /Ar process has a time-independent and a higher etch rate and creates a smooth etched surface while the etch rate of BSO and BTO in CF 4 /Ar plasma decreases with the etching time duration. For the BCl 3 /Ar etching process, the etch rate increases with both ion density and ion energy, suggesting the combination of chemical plasma etching and physical ion sputtering mechanisms. Using the Cl-based etching process, BaSnO 3 and BaTiO 3 heterojunction field effect transistors (FET) are developed. The devices with a gate length of 1.5 µm have a saturation current density of 287.6 mA/mm, a maximum transconductance of g m = 91.3 mS/mm, an FET mobility of 45.3 cm 2 /Vs, and threshold voltage of-1.75 V. The etching processes developed in this work will enable further development of perovskite oxide heterostructure electronic devices.
Journal of Physics D-applied Physics, 2000
Thin films of ferroelectric PbTiO3 (PT) and Pb(Zr0.5 Ti0.5 )O3 (PZT) as well as antiferroelectric PbZrO3 (PZ) have been prepared on LaNiO3 /SiO2 /Si substrates by nebulized spray pyrolysis (NSP) of metal-organic precursors. The metallic LaNiO3 (LNO) electrode layer was also deposited by NSP. The ferroelectric films obtained show satisfactory morphology and desirable dielectric properties. Typical values of the coercive field, remnant polarization and dielectric constant (300 K) for the PT/LNO/SiO2 /Si film are 170 kV cm-1 , 22 µC cm-2 and 210, respectively, with the corresponding values for the PZT/LNO/SiO2 /Si film being 120 kV cm-1 , 13 µC cm-2 and 540, respectively. The PZ/LNO/SiO2 /Si film shows typical antiferroelectric characteristics including the electric-field induced reversible antiferroelectric - ferroelectric transition. The various films deposited on LNO/SiO2 /Si by NSP are comparable in all respects to those prepared on Pt/Ti/SiO2 /Si by the same technique.
Pb 0.90 La 0.15 TiO 3 ͑PLT15͒ thin films were deposited by the sol-gel method on Pt, Pt/Si, and RuO 2 on Si and Pt/Si bottom electrodes. X-ray diffraction, micro-Raman spectroscopy, and atomic force microscopy techniques were used for structural characterization of these films. PLT15 films on different electrodes showed good surface morphology with dense and uniform microstructure. PLT15 films on solution derived RuO 2 bottom electrodes show ͑100͒ preferred orientation of growth and result in larger crystallites. Films deposited on a Pt bottom electrode show sharp and intense Raman features indicating better crystallinity and insignificant film-electrode interactions. PLT15 film on a Pt bottom electrode exhibited higher dielectric constant ͑1300 at 100 kHz͒ and high values of P m and P r , 68 and 46 C/cm 2 , respectively, compared to other electrodes. Films on a RuO 2 bottom electrode showed relatively inferior dielectric and ferroelectric properties. The ac field dependence of dielectric permittivity at subswitching fields was fitted using the Rayleigh law. It was found that ϳ22% of the total measured permittivity was due to irreversible domain wall displacement for the films on a Pt electrode. The reversible polarization components estimated from the capacitance-voltage (C-V) and quasistatic hysteresis measurements showed that P rev / P sat at V max for the case of Pt/Si ͑24%͒, was larger than that of Pt ͑11%͒ bottom electrodes. The observed results were correlated with the domain wall pinning at the disturbed film-electrode interface.
Materials Science Forum, 2006
Three types of bottom electrodes were deposited by RF magnetron sputtering on SiO 2 /Si substrates: LaNiO 3 (LNO), Pt/Ti and LNO/Pt/Ti. The effect of different deposition and processing conditions for the LNO films on the ferroelectric properties of sputtered Pb(Zr 0.52 Ti 0.48 )O 3 (PZT) capacitors was investigated. The LNO films were either deposited at room temperature and heattreated in O 2 flow in the furnace at 500 or 600ºC or made in situ in the range of 200-500ºC. Other deposition parameters under study were the pressure, the RF power and the Ar:O 2 ratio. The resistivity of the LNO films was measured and on some of the films with the lower values, amorphous PZT was deposited and then crystallized in the furnace. X-ray diffraction results show that the PZT films deposited over Pt/Ti had a preferential (100) orientation, while those deposited over LNO made in situ are strongly (100) oriented and the ones deposited over amorphous LNO do not exhibit any preferential orientation. The remanent polarization of the capacitors was around 28µC/cm 2 when amorphous LNO or Pt/Ti electrodes were used and around 20µC/cm 2 with LNO made in situ. Leakage currents were improved when LNO electrodes made in situ was used; a good ferroelectric fatigue performance of the capacitors when subjected to 10 10 switching cycles was also observed.
Role of morphological characteristics on the conductive behavior of LaNiO3 thin films
Ceramics International, 2016
LaNiO 3 (LNO) thin films were synthesized via the polymeric precursor method and sintered using conventional and microwave heating sources. The samples were characterized by structural morphological and electrical techniques. The crystalline structure was analyzed by X-ray diffraction and indicated rhombohedral perovskite phase in both films sintered using conventional and microwave heating. The films morphology was evaluated by scanning and transmission electron microscopy, and atomic force microscopy, and the results point out that microwave heating exerts direct influence on the morphological characteristics of LNO films contributing towards the change in the grain size distribution, porosity and roughness. Conductivity was also investigated through four-probe measurements, which pointed out a conductive and ohmic behavior of the LNO thin films prepared via the polymeric precursor method where a direct relationship was found between the morphological characteristics and the electrical properties of LNO film.
Micro/Crystal structure analysis of CSD derived porous LaNiO3 electrode films
Journal of the Ceramic Society of Japan, 2013
LaNiO 3 (LNO) is one of an excellent candidate for oxide electrodes especially for perovskite ferroelectric films since it is perovskite type crystal structure, and therefore it is suitable for lattice matching with conventional perovskite ferroelectrics, Pb(Zr,Ti)O 3 (PZT), BaTiO 3 (BTO), etc. We have been investigating an effect of thermal expansion of the LNO film as PZT/LNO/ Si and BTO/LNO/Si structures, where ferroelectric and piezoelectric properties can be improved by a compressive thermals stress implied from the LNO layer to the ferroelectric films. The ferroelectric films also shows high [001] orientation owing to [100] orientation of the LNO film. In the present study, microstructures and crystal structures of the LNO films fabricated on Si substrates by CSD method is investigated by X-ray Diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) in order to understand self-orientation along [100] perpendicular to the film plane. The results obviously indicate that the 1 layer deposited LNO film has almost no orientation, whereas it shows tendency of orientation of [100] perpendicular to the film plane when the layer number increased (upto 4 layers). TEM analysis also shows inplane tensile stress applied to the LNO film is effectively decreased by porous LNO structure, which leads in-plane compressive stress to the ferroelectric films prepared on the LNO films.
Morphological and Structural Evolution of Chemically Deposited Epitaxially LaNiO3 Thin Films
Coatings, 2021
We report the preparation and characterization of epitaxial LaNiO3 (LNO) thin films by chemical solution deposition method using lanthanum and nickel acetylacetonates as starting reagents dissolved in propionic acid. In order to obtain further information regarding the decomposition behavior of the film, the precursor solution was dried to obtain the precursor powder, which was investigated by thermal analyses and X-ray diffraction measurements (XRD). The LNO perovskite thin films were deposited by spin coating on SrTiO3(100) single crystal substrates. A detailed study with different crystallization temperatures (600–900 °C) at two different heating ramps (5 and 10 °C/min) was performed. Oriented LaNiO3 thin films with good out-of-plane textures were obtained with optimal surface morphologies.