High-ĸ 소자 응용을 위한 도핑된 HfO2 기반 멀티레이어 산화물의 유전 특성 제어에 관한 이론적 고찰

초록

As the scaling of next-generation semiconductor devices accelerates, ensuring high capacitance while suppressing leakage current has become crucial. Consequently, the development of high-permittivity (high-ĸ) gate dielectrics is now a critical challenge. In particular, hafnium oxide (HfO2) has emerged as a key material to replace conventional silicon-based insulators. However, further enhancement of its dielectric performance and precise control of its physical properties are essential to maximize device efficiency. In this study, Density Functional Theory (DFT) was employed to investigate the changes in dielectric performance, structural modifications, and electronic properties of HfO2 under high-concentration doping conditions. To clearly isolate the effects of specific dopants, a multilayer oxide structure was modeled by substituting a significant portion of the unit cell with dopant atoms. Structural optimization, dielectric constant evaluation, and density of states analysis were performed using the Vienna Ab initio Simulation Package. The results demonstrate that the substitution with most dopants leads to an increase in the dielectric constant of HfO2, which was further analyzed by separating the ionic and electronic dielectric contributions. A clear correlation was established between the structural distortion of the crystal lattice, changes in charge transport paths, and the emergence of trap sites. These factors were identified as the primary drivers of the enhanced dielectric performance. Consequently, this study provides an essential theoretical foundation for controlling the physical properties of HfO2. It also suggests a strategic approach for optimizing various oxide-based high-ĸ thin films through precise dopant control.

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