The niobium doping effects on resistance degradation of strontium titanate thin film capacitors

The rate of resistance degradation of thin (<450 Å) niobium-doped strontium titanate polycrystalline films with platinum top electrodes and iridium bottom electrodes was investigated as a function of direct current (dc) voltages, temperature, Nb atomic fractions [Sr(Ti1−xNbx)O3+y, x=0, 0.001, 0.01, and 0.05, respectively], and capacitor areas (from 2.50×10−5 to 2.91×10−3 cm2). It was found that by increasing the amount of niobium, the resistance degradation rates were greatly reduced, but the leakage currents increased. Also, the degradation rates seemed fairly independent of the areas of the devices.