Infrared and electrical properties of amorphous sputtered (LaxAl1-x)2O3 films

Amorphous (LaxAl1-x)(2)O-3 (0.61less than or equal toxless than or equal to0.73) films have been deposited by sputtering in a partially reactive atmosphere. The average dielectric constant of the as-deposited films was 13.4 and 12.5 following annealing at 700 degreesC for 60 min in N-2; both values were much lower than the single crystal values similar to24 and 28 for LaAlO3 and La2O3, respectively. Leakage current densities were similar to10(-8) A cm(-2) for an applied field of 1 MV cm(-1) for film thicknesses similar to75 nm. Fourier transform infrared spectroscopy reveals transverse optic mode peaks at 723 and 400 cm(-1) and corresponding longitudinal optic modes at 821 and 509 cm(-1). The density of the amorphous phase is estimated to be similar to0.9 times the crystalline density. (C) 2003 American Institute of Physics.