AVS 45th International Symposium
    Electronic Materials and Processing Division Thursday Sessions
       Session EM-ThP

Paper EM-ThP1
Synthesis and I-V Characterization of Tin Dioxide Varistors

Thursday, November 5, 1998, 5:30 pm, Room Hall A

Session: Electronic Materials and Processing Poster Session
Presenter: A. Kale, University of Central Florida
Authors: A. Kale, University of Central Florida
R.N. Barve, College of Engineering, India
S.K. Date, National Chemical Laboratories, India
P.N. Santhosh, Indian Institute of Science, India
S. Seal, University of Central Florida
Correspondent: Click to Email
Tin dioxide varistors are novel semiconducting ceramics having interesting non-ohmic current-voltage characteristics. They are widely used in consumer and military electronics, industrial protection, communications, transportation, data processing and other applications like medical devices. An overview of the steady state time dependent electrical properties of Tin dioxide varistors is presented. For a quantitative agreement with the experimental data the electronic defect states in the bulk of the Tin dioxide grains and at the interfaces between the grains were studied. The varistors were fabricated in two ways. The normal physical process (ceramic route) of mixing and compaction of Tin dioxide powder with various dopants and the second method being that of sol-gel processing in which dopants were taken in their aqueous solutions. Samples prepared by both the processes were studied for the dopant densification using Scanning Electron Microscope and X-ray diffraction. The effect of various sintering temperatures on their non-ohmic or non-linear characteristics was also studied. The varistors prepared by the sol-gel method showed high non-linearity, high density and high threshold voltage properties than the ceramic route owing to their finer grain structure and better densification of dopants around the grain boundaries. It was shown that the Tin dioxide non-linear properties are a function of grain size and depend upon the factors that influence the course of events at the sintering temperature. It is hoped that in coming years, the research efforts are likely to have path breaking impacts in design and development of better varistors