Improvement of the dielectric properties of Ta2O5 through substitution with Al2O3

For bulk ceramic materials, small substitutions of Al2O3 in Ta2O5 are shown to cause a moderate enhancement of the dielectric constant. For compositions near 0.95Ta2O5 endash 0.05Al2O3, the temperature coefficient of the dielectric constant at 20 degree C dramatically decreases, from more than 200 ppm/degree C for pure Ta2O5 to less than 20 ppm/degree C. The quality factors (Q) at 1 MHz, are 2000 endash 5000. Measurements to 14 GHz at 20 degree C show that the dielectric constant is maintained to microwave frequencies, with a Q of ∼600 at 5 GHz. copyright 1997 American Institute of Physics