Phase composition, microstructure, electrical and thermal properties of TiN and Yb2O3-Sm2O3 doped AlN ceramics

Abstract

The phase composition, microstructure, electrical and thermal properties of hot-pressed AlN-2 wt% Yb2O3-4 wt% Sm2O3-x wt% TiN (x = 0, 0.4, 0.8, 1, 2, 3, 4) ceramics were systematically investigated. Yb2O3 and Sm2O3 were used to react with Al2O3 in AlN to form Yb3Al5O12, SmAlO3 and SmAl11O18, which made the samples densely sintered. When sintered at higher than 1700 °C, the electrical resistivity of AlN ceramics with 2 wt% Yb2O3-4 wt% Sm2O3 decreased significantly to 1010 Ω·cm. This decrease in resistivity was probably caused by the continuity of the secondary phase, which encasing the AlN grains and deteriorating the thermal conductivity. When sintered at 1650 °C, the addition of 0.4–4.0 wt% TiN reduces the electrical resistivity from 8.9 × 1012 to 2 × 1010 Ω·cm while maintaining thermal conductivity at around 90 W/m·K with high compactness. Finally, a series of high performance AlN ceramics, with adjustable electrical/thermal properties, could be obtained for modern semiconductor industry.