An Experimental Investigation of the Dielectric Properties of Thermally Evaporated Rare Earth Oxides for Use in Thin Film Capacitors

An experimental survey of rare earth oxides for use in thin film capacitors has been completed. Dielectric properties measured at 300°K are reported for thermally evaporated oxides 300 to 6000 Å in thickness of the metals, La, Ce, Pr, Nd, Sm, Gd, Dy, Ho, Er, Yb, Y, Sc, and also, V. Thin evaporated aluminum electrodes were utilized to impress voltages in the range zero to 75 V across the oxide layers. Dielectric breakdown strengths in excess of 5 × 106 V/cm were observed. Relative dielectric constants measured for the oxides range from two to twenty, and measured capacitances were as high as 156 × 10−9 F/cm2. The oxides of Ce, La, Nd, Gd, Pr, and Er show the most promise as potential materials for use in thin film capacitors.