STRUCTURAL AND ELECTRICAL-PROPERTIES OF CRYSTALLINE (1-X)TA2O5-XAL(2)O(3) THIN-FILMS FABRICATED BY METALORGANIC SOLUTION DEPOSITION TECHNIQUE

Polycrystalline (1-x)Ta2O5-xAl(2)O(3) thin films were fabricated by me talorganic solution deposition technique on Pt-coated Si substrate at a temperature of 750 degrees C. Thin films with 0.9Ta(2)O(5)-0.1Al(2)O (3) composition exhibited improved dielectric and insulating propertie s compared to Ta2O5 thin films. The measured small signal dielectric c onstant and dissipation factor at 100 kHz were 42.8 and 0.005, respect ively. The temperature coefficient of capacitance was 20 ppm/degrees C in the measured temperature range of 25-125 degrees C. The leakage cu rrent density was lower than 6 x 10(-8) A/cm(2) up to an applied elect ric field of 1 MV/cm. A charge storage density of 18.9 fC/mu m(2) was obtained at an applied electric field of 0.5 MV/cm. The high dielectri c constant, low dielectric loss, low leakage current density. and good temperature and bias stability suggest (1-x)Ta2O5-xAl(2)O(3) thin fil ms to be a suitable dielectric layer in integrated electronic devices in place of conventional dielectrics such as SiO2 or Si3N4. (C) 1997 A merican Institute of Physics.