Scanning Probe Microscopy on heterogeneous CaCu3Ti4O12 thin films

Fiorenza, Patrick; Nigro, Raffaella Lo; Raineri, V.

doi:10.1186/1556-276x-6-118

Cited by 7 publications

(4 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The dielectric constant of the CCTO films greatly depends on the conductivities of grains and grain boundaries. According to the internal barrier layer capacitor model, the films having semiconducting grains with insulating grain boundaries show higher dielectric permittivity [36]. In contrast, the films grown at 45 W have shown lower dielectric constant (169) at 1 KHz.…”

Section: Resultsmentioning

confidence: 95%

Effect of RF sputtering power on morphological and electrical properties of calcium copper titanate thin films

Tripathy

Das

Ghosh

et al. 2017

J Mater Sci: Mater Electron

View full text Add to dashboard Cite

dielectric constant, but these are limited to low temperature applications. Beyond the Curie temperature (T c ) their dielectric properties decreases dramatically, which is undesirable for device applications. Recently, CaCu 3 Ti 4 O 12 (CCTO), possessing a distorted cubic perovskite structure, has received intensive consideration due to its extraordinary dielectric behavior [7]. The dielectric constant of CCTO ceramics is in the order of 10 5 over a broad range of temperature due to its stable cubic structure [8] and also no lattice distortion has been observed in CCTO between this temperature range as confirmed by neutron diffraction and high resolution X-ray diffraction [7,8]. The origin of high permittivity in CCTO is still under debate. High dielectric behavior is the common feature in ferroelectric materials. In case of CCTO, the contribution from dipoles has been ruled out due to its centrosymmetry nature even at low temperature [7,8]. The internal barrier layer mechanism is widely accepted for explanation of giant dielectric permittivity in CCTO, where the conducting grains are separated by insulating grain boundaries [9]. Application of CCTO in microelectronics for memory devices, sensors, capacitor and varistors demands the deposition of CCTO thin films on silicon substrate.Due to the unique dielectric behavior of CCTO bulk ceramics, many research groups have initiated deposition of CCTO thin films by different deposition techniques [10-16] on various types of substrates [17][18][19]. Sputtering is considered as one of the most promising deposition technique for thin film deposition [20]. There are very few reports of deposition of CCTO thin film by RF sputtering [12,21]. Sputtering parameters like RF power, deposition pressure, substrate temperature strongly influence the structural, morphological and electrical properties of thin films. In our previous work [22], we have deposited CCTO thin film with the variation of deposition pressure on silicon Abstract Calcium copper titanate (CCTO) thin films were deposited on p-type silicon substrate by RF magnetron sputtering at various RF powers. Post deposition annealing was carried out for all the samples at 950 °C for 1 h in air atmosphere. Various types of surface morphology have been observed for CCTO thin films with the variation of RF power. The evolution of polycrystalline structure of the CCTO thin films was confirmed by XRD studies. The FTIR characteristic absorption band of CCTO was observed in the range of 400-700 cm −1 . The capacitancevoltage (C-V) and current-voltage (I-V) characteristics of the films were investigated employing Al/CCTO/Si MOS capacitors. CCTO films with higher dielectric constant, lower oxide and interface charge density were obtained at higher RF power. Leakage current was also found to be minimum for RF power of 105 W.

show abstract

Section: Resultsmentioning

confidence: 95%

Effect of RF sputtering power on morphological and electrical properties of calcium copper titanate thin films

Tripathy

Das

Ghosh

et al. 2017

J Mater Sci: Mater Electron

View full text Add to dashboard Cite

show abstract

“…This consideration prompted the search for an alternative electrode having a higher thermal stability. Thus, CCTO thin films have been grown, using the same deposition parameters, on the more thermally stable IrO 2 /Ir/TiO 2 /SiO 2 /Si substrate . The obtained CCTO films demonstrated to possess a polycrystalline nature and SEM cross‐section image (Figure d) showed dense CCTO thin films on a flat IrO 2 /Ir surface.…”

Section: Mocvd Process For Cacu3ti4o12 Thin Filmsmentioning

confidence: 99%

“…In particular, it is reported on CCTO thin films deposited on various substrates, ranging from single crystals such as (001)LaAlO 3 and (001)SrTiO 3 . to technological Pt/TiO 2 /SiO 2 /Si(100) and IrO 2 /Ir/TiO 2 /SiO 2 /Si multilayer electrodes. Highly epitaxial CCTO thin films have been fabricated on single crystals as well as polycrystalline CCTO layers have been obtained on substrates of industrial interest.…”

Section: Introductionmentioning

confidence: 99%

MOCVD Approach to the Growth of Calcium Copper Titanate (CaCu₃Ti₄O₁₂) Thin Films: The Role of the Substrate Nature on Film Structural and Dielectrical Properties

Nigro

2017

Adv Materials Inter

Self Cite

View full text Add to dashboard Cite

range. [7][8][9] The CaCu 3 Ti 4 O 12 (CCTO) perovskite has been defined "giant-κ" materials, and looked suitable for high capacity density planar condensers representing key devices for wireless communication. In fact, since it did not show any ferroelectric transition or relaxor behaviour, appeared really attractive for the replacement of ferroelectrics, which are known for having lower dielectric constant values and stronger temperature dependence. Huge efforts of different research groups have been devoted to determine the origin of such prodigious dielectric response. [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] Some theories tried to correlate the CCTO high-κ value to its peculiar cubic perovskite structure. [10][11][12] In fact, it has been demonstrated that the Ti 4+ symmetry in CCTO is much lower than in a cubic standard ABO 3 perovskite cell, because of the tilting of TiO 6 octahedra caused by the square-planar Cu 2+ ions. [14] Hence, its high permittivity could be due to the local dipole moments associated with off-center displacement of Ti 4+ ions, which could also rule out the pure ferroelectric behaviour. Nevertheless, the most accepted explanation of such huge dielectric constant has been related to the "internal barrier-layer mechanism", which has been discussed in CCTO ceramics in terms of conducting grains and insulating grain boundaries. [13][14][15][16][17][18][19][20][21] All these results have been actually collected on bulk materials, however it is not obvious to find the same properties on thin films. In this context, in order to evaluate the potentiality for a real integration of this novel material in device fabrication, the investigation of thin film dielectric properties has been a mandatory issue. First attempts to grow CCTO thin films have been carried out by pulsed laser deposition technique on perovskite oxide substrates [22][23][24][25] and later on technological substrates such as platinum electrodes on silicon. [26][27][28][29] It has been found that the dielectric constant of CCTO thin films is not as huge as in the case of CCTO ceramics, and that, in best conditions, a dielectric constant value in the order of 1500 can be reached [27] and, most of all, that this value strongly depends on many factors, such as deposition conditions, substrate nature, post-deposition treatments and so on. [29][30][31][32][33][34] Actually, a variation of the dielectric constant value with temperature or frequency has been also observed in ceramics, depending on synthetic method and/or post-sintering conditions. [35][36][37] From these discoveries until CaCu 3 Ti 4 O 12 (CCTO) perovskite has been widely investigated because of its excellent dielectric properties, i.e. huge and constant permittivity upon varying temperature and frequencies, which are really attractive in wireless communication devices. These characteristics have been originally demonstrated in single crystals and ceramics. Hence, huge efforts have been focused on the fabrication and investigation of CCTO thin films. F...

show abstract

“…The transport property of the nanobelts device and the surface states on the (1-D) SnO 2 surface must be cared in order to fabricate the practical application of nanodevices. It is difficult for us investigating the transport property of one single nanobelt in the nanometer scale before atomic force microscopy (AFM), especially the conductive AFM (C-AFM) with a conductive tip; in recent years, more and more are used to investigate the transport property and the surface property on the nanostructure in microscope scales [ 12 - 15 ]. AFM tip coated with metal can serve as the conducting electrode, and the transport property of the nanowires can be studied through the I-V curve recorded by C-AFM technique [ 16 ].…”

Section: Introductionmentioning

confidence: 99%

The current image of single SnO2 nanobelt nanodevice studied by conductive atomic force microscopy

Wang

Cheng

et al. 2011

Nanoscale Res Lett

View full text Add to dashboard Cite

A single SnO2 nanobelt was assembled on a pair of Au electrodes by electric-field assembly method. The electronic transport property of single SnO2 nanobelt was studied by conductive atomic force microscopy (C-AFM). Back-to-back Schottky barrier-type junctions were created between AFM tip/SnO2 nanobelt/Au electrode which can be concluded from the I-V curve. The current images of single SnO2 nanobelt nanodevices were also studied by C-AFM techniques, which showed stripes patterns on the nanobelt surface. The current images of the nanobelt devices correlate the microscopy with separate transport properties measurement together.

show abstract

Scanning Probe Microscopy on heterogeneous CaCu3Ti4O12 thin films

Cited by 7 publications

References 26 publications

Effect of RF sputtering power on morphological and electrical properties of calcium copper titanate thin films

Effect of RF sputtering power on morphological and electrical properties of calcium copper titanate thin films

MOCVD Approach to the Growth of Calcium Copper Titanate (CaCu₃Ti₄O₁₂) Thin Films: The Role of the Substrate Nature on Film Structural and Dielectrical Properties

The current image of single SnO2 nanobelt nanodevice studied by conductive atomic force microscopy

Contact Info

Product

Resources

About

Scanning Probe Microscopy on heterogeneous CaCu3Ti4O12 thin films

Cited by 7 publications

References 26 publications

Effect of RF sputtering power on morphological and electrical properties of calcium copper titanate thin films

Effect of RF sputtering power on morphological and electrical properties of calcium copper titanate thin films

MOCVD Approach to the Growth of Calcium Copper Titanate (CaCu3Ti4O12) Thin Films: The Role of the Substrate Nature on Film Structural and Dielectrical Properties

The current image of single SnO2 nanobelt nanodevice studied by conductive atomic force microscopy

Contact Info

Product

Resources

About

MOCVD Approach to the Growth of Calcium Copper Titanate (CaCu₃Ti₄O₁₂) Thin Films: The Role of the Substrate Nature on Film Structural and Dielectrical Properties