| 학회 | 한국재료학회 |
| 학술대회 | 2021년 가을 (11/24 ~ 11/26, 경주 라한호텔) |
| 권호 | 27권 2호 |
| 발표분야 | A. 전자/반도체 재료 분과 |
| 제목 | Electrical and interfacial properties of dipole in High-k/SiO2 structure according to SiO2 buffer layer |
| 초록 | The thickness of the gate oxide film decreased due to the improved MOS (Metal-Oxide-Semiconductor) density, which causes leakage current density. Leakage current density increases power consumption and reduces device reliability. Therefore, a high-k material having a high dielectric constant has been replaced with a gate oxide layer. However, since interface defects occur due to lattice mismatch between the silicon substrate and the high-k material, a SiO2 buffer layer that reduces the lattice constant difference is required. It is argued that dipoles between high-k and SiO2 are formed depending on the oxygen density of the SiO2 buffer layer. Since thermal stability and interfacial properties of the SiO2 buffer layer are important in MOS capacitors, we tried to check the effect of the oxygen density of the SiO2 film on dipole and flat-band voltage (VFB). Differences in SiO2 oxygen density and interfacial dipole and changes in electrical properties were confirmed. In order to confirm only the difference according to the oxidation method, it was fixed under the same thickness (~2 nm) condition and analyzed. A low-density SiO2 film was formed through H2O2, and high-density ultra-thin SiO2 was formed using Nitric acid oxidation of Si (NAOS) at 120℃ and medium-density through Plasma-enhanced chemical vapor deposition(PE-CVD). In addition, -OH groups remaining on the surface were removed by performing post-metallization annealing (PMA), and electrical characteristics before and after PMA treatment were observed. To determine the effect of the interface dipole on VFB movement, capacitance-voltage (C-V) was measured with a probe station instrument. The leakage current density was confirmed through the current-voltage (I-V). The interfacial defects and electrical properties affecting the electrical properties of the device were calculated based on C-V and I-V analysis. Changes in the thickness and suboxide density of the SiO2 buffer layer were confirmed by X-ray photoelectron spectroscopy (XPS) analysis, and there was a difference in the suboxide density according to the oxidation conditions of the oxide layer. |
| 저자 | 김륜나, 김원진, 나호윤, 임현민, 서동혁, 김우병 |
| 소속 | 단국대 |
| 키워드 | High-k material; SiO₂ layer; flatband voltage; dipole; oxygen density |
