Sodium niobate dielectric doped with barium titanate has potential application in integrated circuits with high packing densities and voltage levels below 5 to 8 volts

Kandler, H. A.

Radke, R. P.

English

NASA Technical Reports Server

A dopant, barium titanate (BaTiO 3 ), for sodium 
niobate (NaNb03) dielectric has been determined to 
have potential application in integrated circuit com-
ponents. Such a dielectric could bring about the 
development of components that have a higher voltage 
capacity, especially capacitors. 
In order to fabricate a suitable sodium niobate di-
electric that will evaporate on an integrated circuit 
substrate, a number of materials including sodium 
carbonate powder were investigated. Although initial 
tests in which only sodium carbonate was used proved 
unsuccessful, those in which a " molten sphere" evapo-
rating technique were employed provided a good 
capacitor dielectric, but its dielectric constant and 
voltage breakdown potential characteristics were not 
high enough. 
The next step in the investigation was to examine a 
series of selected impurities, including lead oxide 
(PbO) and BaTiO 3 . Numerous attempts to optimize 
powder feed control were made with BaTiO 3
 as a 
dopant. These included pre-outgassing in a vacuum 
environment at 200°C for 24 hours, sieving, and 
finally, actually running the powder through the 
hopper in the vacuum system, recovering it, and 
then reusing it. This procedure proved to be so effec-
tive that it became difficult to maintain the speed 
slow enough to prevent excessive amounts of powder 
from arriving at the niobium drop. This problem was 
resolved on a trial-and-error basis by utilizing six 
layers of 40-mesh stainless steel screen in the bottom 
of the hopper. As was previously determined, barium 
titanate was found to produce not only the best 
dielectric, but also acted as an anticoagulant in the 
powder-fe&l controller of the molten-sphere tech-
nique. Both PbO and BaTiO 3 were added to the 
sodium carbonate powder in an attempt to improve
.
May 1970	 Brief 70-10190 
NASA TECH BRIEF 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage commercial 
application. Tech Briefs are available on a subscription basis from the Clearinghouse for Federal Scientific and Technical 
Information, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Division, NASA, Code UT, Washington, D.C. 20546. 
Dopant for Sodium Niobate Capacitor Dielectric 
the voltage breakdown characteristics. Further in-
vestigation, using different ratios of sodium car-
bonate (Na 2 CO 3 ) to barium titanate, led to the 
conclusion that a 4:1 ratio, by weight, gave the best 
results. The average voltage breakdown potential 
was raised from approximately 2 to 3 volts for pure 
sodium carbonate powder to about 5 to 8 volts for 
the doped mixture (sodium carbonate powder and 
barium titanate). In addition, a majority of the di-
electric constants for some mixtures were increased 
to a range of 100 to 200 and several to over 500. Also, 
the dissipation factor of the capacitors was signifi-
cantly improved over those previously noted for the 
PbO-doped film, although this is not a consistent 
phenomenon. 
Notes: 
I. Preliminary experimentation indicates that 
sodium niobate dielectric doped with barium 
titanate has a potential application in integrated 
circuits with high packing densities and voltage 
levels below 5 to 8 volts. For previous work on 
thin-film NaNb03
 capacitors, refer to NASA 
Tech Brief 68-10163. 
2. Requests for further information may be directed 
to:
Technology Utilization Officer 
Manned Spacecraft Center, Code BM7 
Houston, Texas 77058 
Reference: TSP 70-10190 
Patent status: 
No patent action is contemplated by NASA. 
Source: Richard P. Radke
and Harold A. Kandler of
TRW Systems Group
under contract to

Manned Spacecraft Center 
Aft	
(MSC-11773)
Category 01 
This document was prepared under the sponsorship of the National	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States 	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States	 will be free from privately owned rights. 
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Dopant for sodium niobate capacitor dielectric

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