Thin glass film between ultrafine conductor particles in thick-film resistors

Journal Article · Sun May 01 00:00:00 EDT 1994 · Journal of the American Ceramic Society; (United States)

DOI:https://doi.org/10.1111/j.1151-2916.1994.tb05386.x· OSTI ID:7114673

Chiang, Y M ^[1]; Silverman, L A; French, R H ^[2]; Cannon, R M ^[3]

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1. Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Materials Science and Engineering
2. DuPont Co., Wilmington, DE (United States). Central Research and Development
3. Lawrence Berkeley Lab., CA (United States)

Thick-film resistors are electrical composites containing ultrafine particles of ruthenate conductor (Pb[sub 2]Ru[sub 2]O[sub 7] in the present materials) distributed in a highly modified silicate glass. The authors show that conductor particles remain flocced in the absence of any applied or capillary pressures, but are separated at equilibrium by a nanometer-thick film of glass. Microstructures show evidence for liquid-phase sintering, i.e., contact flattening of particles, under van der Waals attraction alone. Titania addition, which in dilute concentrations markedly increases the resistivity, decreases the temperature coefficient of resistance, and improves voltage stability and noise, is found to increase the equilibrium film thickness between particles by a few angstroms. STEM analyses show that the added titania preferentially concentrates in the silicate-rich grain boundary film, as well as at particle-glass interfaces. The roles of interparticle forces and adsorption on the glass film thickness with and without titania are discussed. The large increase in resistivity caused by titania additions is attributed to the increase in film thickness as well as to local chemical changes of two possible types. Titania enrichment within the glass film itself is expected to decrease the local ruthenium ion solubility, and this along with the possible formation of a more insulating titania-substituted surface layer on ruthenate grains will decrease the tunneling conductivity between conductor grains.

• OSTI ID: 7114673
• Journal Information: Journal of the American Ceramic Society; (United States), Journal Name: Journal of the American Ceramic Society; (United States) Vol. 77:5; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602* -- Other Materials-- Structure & Phase Studies
360606 -- Other Materials-- Physical Properties-- (1992-)
CHALCOGENIDES
COMPOSITE MATERIALS
DATA
ELECTRICAL PROPERTIES
ELECTRON MICROSCOPY
EXPERIMENTAL DATA
GLASS
INFORMATION
LEAD COMPOUNDS
LEAD OXIDES
MATERIALS
METALLURGICAL EFFECTS
MICROSCOPY
MICROSTRUCTURE
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
REFRACTORY METAL COMPOUNDS
RUTHENIUM COMPOUNDS
RUTHENIUM OXIDES
TITANIUM COMPOUNDS
TITANIUM OXIDES
TRANSITION ELEMENT COMPOUNDS