Microstructure and Crystallization Behavior of Sol-Gel Prepared BaTiO3 Thin Films

1994 ◽  
Vol 346 ◽  
Author(s):  
M.C. Gust ◽  
L.A. Momoda ◽  
M.L. Mecartney

ABSTRACTThin films of BaTiO3 were prepared by the sol-gel route using barium titanium methoxypropoxide in methoxypropanol. Sols with water of hydrolysis varying between h=0 and h=2 were spun onto (100) Si and Ge coated (100) Si substrates. XRD and analytical TEM were used to study the microstructure and crystallization behavior of these films. Polycrystalline BaTiO3 was obtained by heat treating the films at temperatures between 600 and 750°C using either conventional furnace annealing or rapid thermal annealing. Films prepared from sols having the highest water content tended to crystallize first. The BaTiO3 thin films exhibited a fine grain size on the order of 25–50 nm. No preferred orientation was observed. The effects of the hydrolysis conditions of the sol, the type of heat treatment, and the choice of substrate on the final microstructure of the films are discussed.

2012 ◽  
Vol 512-515 ◽  
pp. 1317-1320
Author(s):  
Fann Wei Yang ◽  
Kai Huang Chen ◽  
Chien Min Cheng

We have investigated the structure and ferroelectric properties of the Bi3.25La0.75Ti3O12 (BLT) thin films on SiO2/Si substrate fabricated by sol-gel method. We used the BLT films were annealed at various temperatures of 600, 650, and 700°C for one hour by conventional furnace annealing (CTA). The temperature dependence of leakage currents densities of ferroelectric BLT thin films. The crystalline structure of the prepared BLT thin films was analyzed by X-ray diffraction (XRD). Field emission scanning electron microscopy (FESEM) was used to observe the film thickness and the surface morphology including grain size and porosity. The leakage current density and capacitance of thin film were measured by HP4156C.


1996 ◽  
Vol 433 ◽  
Author(s):  
M.C. Gust ◽  
L.A. Momoda ◽  
M.L. Mecartney

AbstractBaxSrl−xTiO3 thin films with varying Sr concentration were prepared on Pt coated Si substrates using methoxypropoxide based alkoxide precursors. Films were crystallized by heat treating at 700°C for 30 minutes in an oxygen atmosphere after deposition of each layer. Film thickness ranged from 230 to 260 nm. No evidence of tetragonality was observed in any of the compositions. Films with higher Sr concentrations had a larger average grain size, larger grain size distribution, and increased (111) orientation on (111) oriented Pt. The highest dielectric constant of ˜400 was found for Ba 0.5Sr0.5TiO3, although no direct correlation could be made between the composition and dielectric properties.


2005 ◽  
Vol 20 (11) ◽  
pp. 3094-3101 ◽  
Author(s):  
S.M. Park ◽  
W. Ki ◽  
J. Yu ◽  
H. Du

Cobalt nanoparticles were synthesized on silica thin films by heat treating Co/silica films spun on thermally oxidized Si substrates. The as-deposited films were calcined in vacuum (∼0.03 Torr) for 2 h at 500 °C, followed by reduction in hydrogen at 650 °C for up to 15 h. The reduction process is characterized as one of time-dependent evolution of nanoparticles in both physical appearance and phase nature, eventually leading to the formation of well-dispersed Co nanoparticles, as ascertained by x-ray photoelectron spectroscopy and scanning electron microscopy. Slow conversion of Co ions into metallic Co observed in this study is ascribed to the absence of a Co3O4 phase that forms predominantly during calcination in air. Atomic force microscopy revealed a marked increase in the surface roughness of the film due to the development of nanoparticles. A distinct duplex-layer structure was observed in the reduced film, which consisted of the upper layer laden with nanoparticles and the lower layer essentially particle-free. The growth of the upper layer appears to be controlled by the upward diffusion of Co2+ in the film during the reduction process.


2015 ◽  
Vol 3 (9) ◽  
pp. 2115-2122 ◽  
Author(s):  
Wei Sun ◽  
Jing-Feng Li ◽  
Qi Yu ◽  
Li-Qian Cheng

We prepared high-quality Bi1−xSmxFeO3 films on Pt(111)/Ti/SiO2/Si substrates by sol–gel processing and found rhombohedral–orthorhombic phase transition with enhanced piezoelectricity.


1991 ◽  
Vol 235 ◽  
Author(s):  
Ying Wu ◽  
W. Savin ◽  
T. Fink ◽  
N. M. Ravindra ◽  
R. T. Lareau ◽  
...  

ABSTRACTExperimental analysis and simulation of the formation and electrical characterization of TiSi2/+/p-Si shallow junctions are presented here. The formation of shallow n+-p junction, by ion implantation of As through Ti films evaporated on p-Si substrates followed by Rapid Thermal Annealing (RTA) and conventional furnace annealing has been performed in these experiments. Structural techniques such as Secondary Ion Mass Spec-troscopy (SIMS) and Rutherford Backscattering (RBS) experiments have been employed to characterize these devices. RUMP simulations were used to analyze and interpret the RBS data. Current-voltage characteristics have been simulated using PISCES simulator.


2011 ◽  
Vol 197-198 ◽  
pp. 1781-1784
Author(s):  
Hua Wang ◽  
Jian Li ◽  
Ji Wen Xu ◽  
Ling Yang ◽  
Shang Ju Zhou

Intergrowth-superlattice-structured SrBi4Ti4O15–Bi4Ti3O12(SBT–BIT) films prepared on p-Si substrates by sol-gel processing. Synthesized SBT–BIT films exhibit good ferroelectric properties. As the annealing temperature increases from 600°C to 700°C, the remanent polarization Prof SBT–BIT films increases, while the coercive electric field Ecdecreases. SBT–BIT films annealed at 700°C have a Prvalue of 18.9µC/cm2which is higher than that of SBT (16.8µC/cm2) and BIT (14.6µC/cm2), and have the lowest Ecof 142 kV/cm which is almost the same as that of SBT and BIT. The C-V curves of Ag/SBT-BIT/p-Si heterostructures show the clockwise hysteresis loops which reveal the memory effect due to the polarization. The memory window in C-V curve of Ag/SBT-BIT/p-Si is larger than that of Ag/SBT/p-Si heterostructure or Ag/BIT/p-Si heterostructure.


2010 ◽  
Vol 663-665 ◽  
pp. 650-653
Author(s):  
Jin Moo Byun ◽  
Jeong Sun Han ◽  
Jae Hyoung Park ◽  
Seong Eui Lee ◽  
Hee Chul Lee

This study examined the effect of crystalline orientation and dopants such as Nb and Zn on the piezoelectric coefficient of sol-gel driven Pb1(Zr0.52Ti0.48)O3(PZT) and doped PZT thin films. Crack-free 1-μm-thick PZT and doped PZT thin films prepared by using 2-Methoxyethanol-based sol-gel method were fabricated on Pt/Ti/SiO2/Si substrates. The highly (111) oriented PZT thin films of pure perovskite structure could be obtained by controlling various parameters such as a PbTiO3 seed layer and a concentration of sol-gel solution. The Nb-Zn doped PZT thin films exhibited high piezoelectric coefficient which was about 50 % higher than that of undoped PZT thin film. The highest measured piezoelectric coefficient was 240 pC/N, which could be applicable to piezoelectrically operated MEMS actuator, sensor, or energy harvester devices.


1996 ◽  
Vol 433 ◽  
Author(s):  
T. B. Wu ◽  
J. M. Wu ◽  
C. M. Wu ◽  
M. J. Shyu ◽  
M. S. Chen ◽  
...  

AbstractHighly (100)-textured thin film of metallic LaNiO3 (LNO) was grown on the Pt/Ti/SiO2/Si substrates by rf magnetron sputtering at ˜300°C, which was used as a bottom electrode to prepare highly (100)-textured ferroelectric films. Examples on the deposition of PbTiO3, (Pbl−xLax)TiO3, Pb(Zr0.53Ti0.47)O3, Pb[(Mg1/3Nb2/3)1−xTix]O3, and (Ba1−xSrx)TiO3 thin films by rf magnetron sputtering or sol-gel method are shown. A reduction of temperature for perovskite phase formation can be achieved, especially for those difficult to crystallize. The surface roughness of the ferroelectric films is also improved as compared to that of films deposited on conventional Pt electrode. Although the electrical properties of the ferroelectric films are affected by the out-diffusion of LNO when a higher temperature was used in the preparation of the films, under an appropriate processing condition, the highly (100)-textured films can have satisfactory electrical characteristics for application. Moreover, the polarization-fatigue property can be also improved by the use of LNO electrode.


2021 ◽  
Vol 11 (04) ◽  
pp. 2150019
Author(s):  
Chenjing Wu ◽  
Manwen Yao

Compositional-gradient [Formula: see text][Formula: see text]O3 thin films on Pt(100)/Ti/SiO2/Si substrates are fabricated with sol–gel using spin coating. All of the structures of the prepared thin films are of single-phase crystalline perovskite with a dense and crack-free surface morphology. BTS10/15/20 thin film exhibits enhanced temperature stability in its dielectric behavior. The temperature coefficient of capacitance [Formula: see text] in the temperature range from [Formula: see text]C to [Formula: see text]C is [Formula: see text]C and that of [Formula: see text] in the temperature range from [Formula: see text]C to [Formula: see text]C is [Formula: see text]C. Furthermore, the thin films show low leakage current density and dielectric loss. High and stable dielectric tunable performances are found in BTS10/15/20 thin films: the dielectric tunability of the thin films is around 20.1% under a bias voltage of 8 V at 1 MHz and the corresponding dielectric constant is in the range between 89 and 111, which is beneficial for impedance matching in circuits. Dielectric tunability can be obtained under a low tuning voltage, which helps ensure safety. The simulated resonant frequency of the compositional-gradient BTS thin films depends on the bias electric field, showing compositional-gradient BTS thin films could be used in electrically tunable components and devices. These properties make compositional-gradient BTS thin films a promising candidate for dielectric tuning.


2003 ◽  
Vol 784 ◽  
Author(s):  
Se-Yeon Jung ◽  
Woo-Chul Kwak ◽  
Seung-Joon Hwang ◽  
Yun-Mo Sung

ABSTRACTSr0.7Bi2.4Ta2O9 (SBT) thin films were deposited on Pt/Ti/SiO2/Si substrates with and without a seed layer of ∼40 nm thickness using sol-gel and spin coating methods. The influence of seed layer on the phase formation characteristics of SBT thin films was investigated using x-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses. Formation of pyrochlore as well as Aurivillius phase was observed in both the unseeded and seeded SBT films heated at 740°C. However, it was revealed that Aurivillius phase formation was enhanced in seeded SBT thin films and pyrochlore phase formation was highly suppressed. In this study, two possible mechanisms for the suppression of pyrochlore phase formation were proposed from the perspectives of activation energy difference for Aurivillius and pyrochlore phase formation and Bi-ion diffusion to pyrochlore phase.


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