Ion Implantation in Perovskite Type Ferroelectrics.
Progress rept. no. 6 (Final), 1 Nov 76-31 Oct 79,
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The object of this work was to study ion implantation in perovskite ferroelectrics and to investigate the conductive behavior of implanted layers. Implantation experiments were carried out on strontium titanate, barium titanate single crystal and ceramic, titanium dioxide rutile, lithium niobate, and lithium tantalate. Ion beams attempted were H, B, C, N, Fe, Ar, As, Ta, and Nb. In general the most effective ion in producing conductivity was boron, B. Significant conductivity was measured in the substrates above, except for single crystals of barium titanate and lithium tantalate. Boron implanted in strontium titanate and subsequently annealed resulted in highly conductive layers, whose sheet resistance could be between 100 and 100,000 ohm per square. The charge carrier mobility in this system was 5 sq. cmvolt sec at room temperature, increasing to 100 sq. cmvolt sec at 77 K. Implantation doses were 10 to the 16th power to 10 to the 17th power ionssq. cm. The implantation depth, as revealed by chemical stripping experiments, was about 500 nm. A conductive anomaly was measured in some samples at 105 K, the cubic-tetragonal transition temperature.
- Physical Chemistry