Structural and electrical properties of HfO2 with top nitrogen incorporated layer

A novel technique to control the nitrogen profile in HfO2 gate dielectric was developed using a reactive sputtering method. The incorporation of nitrogen in the upper layer of HfO2 was achieved by sputter depositing a thin HfxNy layer on HfO2, followed by reoxidation. This technique resulted in an improved output characteristics compared to the control sample. Leakage current density was significantly reduced by two orders of magnitude. The thermal stability in terms of structural and electrical properties was also enhanced, indicating that the nitrogen-doped process is effective in preventing oxygen diffusion through HfO2. Boron penetration immunity was also improved by nitrogen-incorporation. It is concluded that the nitrogen-incorporation process is a promising technique to obtain high-k dielectric with thin equivalent oxide thickness and good interfacial quality.