Effective p-type doping for leakage current reduction of ZrO2 by employing Sc2O3

초록

This study explores the integration of scandium oxide (Sc2O3) as a novel p-type dopant to enhance the performance of zirconium dioxide (ZrO2)-based metal-insulator-metal (MIM) capacitors. Compared to traditional aluminum oxide (Al2O3) inserting layers, Sc2O3 exhibits superior structural compatibility with ZrO2, effectively preserving crystallinity and minimizing grain size degradation. Systematic evaluations reveal that employing Sc2O3 as an inserting layer (IL) prevents significant crystallinity degradation up to a thickness of 1 nm and only slight deterioration at 2 nm. This effect is particularly pronounced in ultrathin ZrO2 films, where Sc2O3 also promotes a transition to the cubic phase, mitigating k-value reduction. Furthermore, Sc3+ doping significantly reduces leakage current without compromising the dielectric constant. Consequently, the Sc2O3-based ZrO2 (ZSZ) structure achieved a minimum equivalent oxide thickness (tox) of 0.71 nm, marking a 5.3 % improvement over pristine ZrO2. These findings establish Sc2O3 as a promising alternative to conventional Al2O3 for advancing high-k dielectric applications.

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