Structural and electrical properties of crystalline (1-x)Ta2O5-xAl(2)O(3) thin films fabricated by metalorganic solution deposition technique

Abstract

Polycrystalline (1-x)Ta2O5-xAl(2)O(3) thin films were fabricated by metalorganic 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 properties compared to Ta2O5 thin films. The measured small signal dielectric constant and dissipation factor at 100 kHz were 42.8 and 0.005, respectively. The temperature coefficient of capacitance was 20 ppm/degrees C in the measured temperature range of 25-125 degrees C. The leakage current density was lower than 6 x 10(-8) A/cm(2) up to an applied electric 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 dielectric constant, low dielectric loss, low leakage current density. and good temperature and bias stability suggest (1-x)Ta2O5-xAl(2)O(3) thin films to be a suitable dielectric layer in integrated electronic devices in place of conventional dielectrics such as SiO2 or Si3N4. (C) 1997 American Institute of Physics.