Mallem Kumar, Jagadeesh Chandra S V, Ju Minkyu, Dutta Subhajith, Ramana C H V V, Hussain Shahzada Qamar, Park Jinjoo, Kim Youngkuk, Cho Young-Hyun, Cho Eun-Chel, Yi Junsin
Information and Communication Device Laboratory, School of Information and Communication Engineering, Sungkyunkwan University, 2066, Seobu-ro, jangan-gu, suwon-si, gyeong gi-Do, 16419, Republic of Korea.
Department of Electronics and Communication Engineering, Lakireddy Bali Reddy College of Engineering, Mylavaram 521230, Andhra Pradesh, India.
J Nanosci Nanotechnol. 2020 Feb 1;20(2):1039-1045. doi: 10.1166/jnn.2020.16934.
We report the effects of the nitride passivation layer on the structural, electrical, and interfacial properties of Ge metal-oxide-semiconductor (MOS) devices with a hafnium oxide (HfO₂) gate dielectric layer deposited on -type 〈100〉 Ge substrates. X-ray photoelectron spectroscopy analysis confirmed the chemical states and formation of HfO₂/Ge₃N₄ on Ge. The interfacial quality and thickness of the layers grown on Ge were confirmed by high-resolution transmission electron microscopy. In addition, the effects of post-deposition annealing (PDA) on the HfO₂/Ge₃N₄/Ge and HfO₂/Ge samples at 400 °C in an (FG+O₂) ambient atmosphere for 30 min were studied. After PDA, the HfO₂/Ge₃N₄/Ge MOS device showed a higher dielectric constant () of ~21.48 and accumulation capacitance of 1.2 nF, smaller equivalent oxide thickness (EOT) of 1.2 nm, and lower interface trap density () of 4.9×10 cm eV and oxide charges () of 7.8×10 cm than the non-annealed sample. The analysis showed that the gate leakage current density of the HfO₂/Ge₃N₄/Ge sample (0.3-1 nA cm at = 1 V) was half of that of the HfO₂/Ge sample. Moreover, the barrier heights of the samples were extracted from the Fowler-Nordheim plots. These results indicated that nitride passivation is crucial to improving the structural, interfacial, and electrical properties of Ge-based MOS devices.
我们报告了氮化物钝化层对在 - 型〈100〉锗衬底上沉积有氧化铪（HfO₂）栅极介电层的锗金属氧化物半导体（MOS）器件的结构、电学和界面特性的影响。X射线光电子能谱分析证实了锗上HfO₂/Ge₃N₄的化学状态和形成情况。通过高分辨率透射电子显微镜确认了在锗上生长的层的界面质量和厚度。此外，研究了在（FG + O₂）环境气氛中于400°C对HfO₂/Ge₃N₄/Ge和HfO₂/Ge样品进行30分钟的沉积后退火（PDA）的影响。PDA处理后，HfO₂/Ge₃N₄/Ge MOS器件显示出更高的介电常数（~21.48）和1.2 nF的积累电容，更小的等效氧化层厚度（EOT）为1.2 nm，以及比未退火样品更低的界面陷阱密度（4.9×10¹¹ cm⁻² eV⁻¹）和氧化层电荷（7.8×10¹¹ cm⁻²）。电学分析表明，HfO₂/Ge₃N₄/Ge样品在V = 1 V时的栅极漏电流密度（0.3 - 1 nA cm⁻²）是HfO₂/Ge样品的一半。此外，从福勒 - 诺德海姆曲线提取了样品的势垒高度。这些结果表明，氮化物钝化对于改善锗基MOS器件的结构、界面和电学特性至关重要。
