Diffuse phase transitions, electrical conduction, and low temperature dielectric properties of sol–gel derived ferroelectric barium titanate thin films

2001 ◽  
Vol 90 (3) ◽  
pp. 1480-1488 ◽  
Author(s):  
Reji Thomas ◽  
V. K. Varadan ◽  
S. Komarneni ◽  
D. C. Dube
1994 ◽  
Vol 346 ◽  
Author(s):  
R. P. S. M. Lobo ◽  
R. L. Moreira ◽  
N. D. S. Mohallem

ABSTRACTBarium titanate ceramics have been obtained by sol-gel methods. The dielectric investigations of these materials revealed the existence of diffuse ferroelectric transitions. By using a phenomenological model, we could demonstrate the existence of a simple relationship between the diffuse character of the transition and the sample grain-size. This effect has been attributed to interactions between charged defects on the grain surfaces and the spontaneous polarization of the material.


2001 ◽  
Vol 117 (5) ◽  
pp. 315-319 ◽  
Author(s):  
Hu-Yong Tian ◽  
Wei-Gen Luo ◽  
Xing-Hua Pu ◽  
Ping-Sun Qiu ◽  
Xi-Yun He ◽  
...  

2010 ◽  
Vol 1247 ◽  
Author(s):  
Manish Kumar ◽  
Shu Xiang ◽  
P. Markondeya Raj ◽  
Isaac Robin Abothu ◽  
Jin-Hyun Hwang ◽  
...  

AbstractThere is an increasing need for integrating high dielectric constant ceramic thin film components in organic and 3D IC packages to lower the power-supply impedance at high frequencies and supply noise-free power to the ICs. Sol-gel approach is very attractive for high density capacitors because of its ability to precisely control the composition of the films and the ease of introducing dopants to engineer the dielectric properties such as breakdown voltages and DC leakage characteristics. Thin films on copper foils lend themselves to organic package integration with standard foil lamination techniques used in package build-up processes. However, fabrication of thin film barium titanate on copper foils is generally affected by process incompatibility during crystallization in reducing atmospheres, leading to poor crystallization, oxygen vacancies and copper diffusion through the film that degrades the electrical properties.This paper focuses on the dielectric properties and electrical reliability of thin films on copper foils. Thin film (300-400 nm) embedded capacitors with capacitance density of 2 μF/cm2, low leakage current and high breakdown voltage were fabricated via sol-gel technology and foil lamination. To lower the leakage current, the chemical composition was altered by incorporating – 1.) Excess barium 2.) Acceptor dopants such as Mn. Both approaches lowered the leakage current compared to that of pure barium titanate. SEM analysis showed enhanced densification and refined grain structure with chemistry modification. The films showed good stability in leakage currents at 150 C with an applied field strength of 100 kV/cm, demonstrating the electrical reliability of these films.


1997 ◽  
Vol 82 (9) ◽  
pp. 4484-4488 ◽  
Author(s):  
Reji Thomas ◽  
D. C. Dube ◽  
M. N. Kamalasanan ◽  
Subhas Chandra ◽  
A. S. Bhalla

2011 ◽  
Vol 311-313 ◽  
pp. 1481-1484 ◽  
Author(s):  
Xiao Fang Cheng ◽  
Xin Gui Tang ◽  
Shao Gong Ju ◽  
Yan Ping Jiang ◽  
Qiu Xiang Liu

The 0.94Bi0.5Na0.5TiO3-0.06BaTiO3 (abbreviated to BNT-BT) powder and ceramic was synthesized by sol-gel process. The phase structure and dielectric properties of the ceramics were investigated. The ceramic was sintering at 1000-1100 degree C for 2-4 h in air atmosphere, and the X-ray diffraction (XRD) results revealed that the samples was pure perovskite-type phase. The Curite temperature of BNT-BT ceramics was high up to 348 degree C. The temperature dependence of dielectric permittivity and loss revealed there were two phase transitions, which were from ferroelectric (tetragonal) to anti-ferroelectric (rhombohedral) and anti-ferroelectric to paraelectric (cubic) in BNT-BT ceramics. Diffuse phase transitions were observed in BNT and BNT-BT ceramics and the Curie-Weiss Exponent (CWE) were nearly 2.


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