Ion-Implanted Epitaxially Grown Gd2O3 on Silicon with Improved Electrical Properties

The effects of nitrogen incorporation by high-dose ion implantation in epitaxial gadolinium oxide (Gd2O3) films on Si (111) followed by annealing have been investigated. The nitrogen content in the oxide layer was changed by altering the implantation dose. The presence of nitrogen incorporation on the Gd2O3 layer was studied using Auger electron spectroscopy. Nitrogen incorporation is believed to occur by filling the oxygen vacancies or by removing hydroxyl group ions in Gd2O3. A maximum concentration of 11% was obtained for nitrogen in the interface between the silicon dioxide and Gd2O3 layer and the implanted areas of the Gd2O3 oxide layer after sputter depth profiling. The nitrogen distribution in the layer was found to be non-uniform. Nitrogen incorporation sharply reduced the leakage current and effectively suppressed the hysteresis. Leakage current was two orders lower compared with the pure Gd2O3.