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 temperature coefficient of the dielectric constant at 20 degrees C dramatically decreases, from more than 200 ppm/degrees C for pure Ta2O5 to less than 20 ppm/degrees C. The duality factors (Q) at 1 MHz, are 2000-5000. Measurements to 14 GHz at 20 degrees C show that the dielectric constant is maintained to microwave frequencies, with a Q of similar to 600 at 5 GMz. (C) 1997 American Institute of Physics.