Plasma-nitrided high-k polycrystalline nano-array induced by electron irradiation

The microstructure of plasma-nitrided high-k ZrO₂ thin films is found to continuously transform and larger size nano-crystals are formed during electron bombardment. Real-time high-resolution transmission electron microscopy (HRTEM) studies show that the plasma-nitrided nano-size particles can self-crystallize and regrow, whereas this phenomenon is not observed in amorphous ZrO₂ without N incorporation. Similar results are observed in plasma-nitrided HfO₂ samples and fine-scale polycrystalline nano-arrays are obtained by electron irradiation. Our results show that incorporation of N is crucial for inducing microstructural evolution as well as polycrystalline nano-array formation in high-k oxide under electron irradiation.