A Study on the Improvement of Characteristics of BST Thin Films Fabricated on Iridium Electrode

1997 ◽  
Vol 493 ◽  
Author(s):  
Deok-Sin Kil ◽  
Byung-Il Lee ◽  
Seung-Ki Joo

ABSTRACTBST thin films have been fabricated by RF magnetron sputtering onto Ir layer as a bottom electrode. When the substrate temperature was maintained at 600 °C during deposition, BST films deposited at that temperature showed very small oxide equivalent thickness of 0.36nm as well as very low leakage current density of about 10−8A/cm2at 1.5V. But as substrate temperature was increased to 700 °C in order to obtain high dielectric constant, oxide equivalent thickness exhibited very low value of about 0.3nm, however, leakage current density drastically increased to 10−4/cm2. BST thin films were fabricated by two step process, which consists of bottom layer deposited at high substrate temperature of 700 °C and top layer deposited at low substrate temperature. In the case of BST thin films which are composed of 20nm thick bottom layer deposited at 700 °C and 30nm thick top layer deposited at 500 °C, we obtained very small oxide equivalent thickness of 0.31nm and low leakage current density of 4 × 10−8A/cm2. at 1.5V.

2002 ◽  
Vol 748 ◽  
Author(s):  
Suprem R. Das ◽  
Rasmi R. Das ◽  
P. Bhattacharya ◽  
Ram S. Katiyar

ABSTRACTPulsed laser deposition technique was used to fabricate Ba0.5Sr0.5TiO 3 (BST) thin-films on Pt/TiO 2/SiO2/Si substrates. The influence of thin interfacial layers of Ta2O5, TiO2, and ZrO2, on the structural and electrical properties of BST thin films was investigated. Insertion of interfacial layers does not affect the perovskite phase formation of BST thin films. Buffer layers helped to make uniform distribution of grains and resulted in a relative increase in the average grain size. The dielectric tunability of BST thin films was reduced with the presence of buffer layers. A BST thin film having a dielectric permitivity of 470 reduced to 337, 235 and 233 in the presence of Ta2O5, TiO2, and ZrO2 layers, respectively. The reduction of the relative dielectric permittivity of BST films with the insertion of interfacial layers was explained in terms of a series capacitance effect, due to the low dielectric constant of interfacial layers. The TiO2 layer did not show any appreciable change in the leakage current density. Deposition of thin Ta2O5 and ZrO2 interfacial layer on top of Pt reduced the leakage current density by an order of magnitude.


1993 ◽  
Vol 310 ◽  
Author(s):  
Jiyoung Kim ◽  
C. Sudhama ◽  
Rajesh Khamankar ◽  
Jack Lee

AbstractIn this work, a high-temperature deposition technique has been developed for ultra-thin sputtered PZT films for ULSI DRAM (<256Mb) storage capacitor applications. In contrast to the previously developed low-temperature (200°C) deposition, deposition at high-temperature (400°C) yields a desirable reduction in grain size of the perovskite phase. The thickness of PZT films has been reduced to less than 30nm with high charge storage density (∼30μC/cm2) and low leakage current density. An optimized 65nm PZT thin film was found to have an equivalent SiO2 thickness of 1.9Å and a leakage current density of less than 10−6 A/cm2 under 2V operation.


2013 ◽  
Vol 741 ◽  
pp. 11-17
Author(s):  
Xiao Hua Sun ◽  
Ya Xia Qiao ◽  
Shuang Hou ◽  
Ying Yang ◽  
Cai Hua Huang

Ba0.6Sr0.4TiO3 (BST) thin films were fabricated by solgel technique on Pt/Ti/SiO2/Si substrate without and with PbO seeding layer from precursor solutions with different concentrations. The crystal structure, surface morphology, dielectric properties and leakage current density of BST thin films are investigated as functions of the concentration of PbO precursor solution. Its found that the growth orientation of BST thin films with PbO seeding layer can be modulated through adjusting the concentration of PbO precursor solution. BST thin film with PbO seeding layer from 0.05 M precursor solution shows the highest dielectric constant and tunability, which may be attributed to the high crystallization and amplitude of the polarization in high (100) preferred orientated films. The leakage current density of BST films increases with the increasing concentration of PbO precursor solution and agrees well with the space-charge-limited current mechanism at room temperature.


2019 ◽  
Vol 2 (1) ◽  
pp. 261-266
Author(s):  
Rosa María Luna-Sánchez ◽  
Ignacio González-Martínez

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