Physical, Electrical, and Reliability Characteristics of Multi-Step Deposition-Annealed HfO_2 Film

摘要

This study compares the physical, electrical, and reliability characteristics of the high-k HfO_2 film that was fabricated by a single-step and a multiple-step deposition-annealed method. After annealing at 750℃, the single-step annealed HfO_2 has transformed into the polycrystalline phase, whereas the multi-step annealed HfO_2 is found to remain in a nanocrystalline phase, revealing that a multi-step deposition-annealing method could greatly improve the thermal stability of the HfO_2 film with respect to the grain formation process. Additionally, the density and composition of the HfO_2 film are enhanced by multi-step deposition-annealing process. These changes lead to an improvement in the electrical characteristics, breakdown voltage, and reliability for the multi-step deposition-annealed HfO_2 film, revealing that the multi-step deposition-annealing method is a promising means for improving the thermal stability and reliability of HfO_2 gate stacks.