Wang Zhenyu, Bai Zhaopeng, Guo Yunduo, Ding Chengxi, Huang Qimin, Gu Lin, Shen Yi, Zhang Qingchun, Ma Hongping
Institute of Wide Bandgap Semiconductors and Future Lighting, Academy for Engineering & Technology, Fudan University, Shanghai 200433, China.
Shanghai Research Center for Silicon Carbide Power Devices Engineering & Technology, Fudan University, Shanghai 200433, China.
Nanomaterials (Basel). 2025 Apr 5;15(7):555. doi: 10.3390/nano15070555.
This study proposed an innovative method for growing gate oxide on silicon carbide (SiC), where silicon oxide (SiO) was fabricated on a deposited AlO layer, achieving high quality gate oxide. A thin AlO passivation layer was deposited via atomic layer deposition (ALD), followed by Si deposition and reoxidation to fabricate a MOS structure. The effects of different ALD growth cycles on the interface chemical composition, trap density, breakdown characteristics, and bias stress stability of the MOS capacitors were systematically investigated. X-ray photoelectron spectroscopy (XPS) analyses revealed that an ALD AlO passivation layer with 10 growth cycles effectively suppresses the formation of the proportion of Si-OC bonds. Additionally, the SiO/AlO/SiC gate stack with 10 ALD growth cycles exhibited optimal electrical properties, including a minimum interface state density () value of 3 × 10 cm eV and a breakdown field () of 10.9 MV/cm. We also systematically analyzed the bias stress stability of the capacitors at room temperature and elevated temperatures. Analysis of flat-band voltage (Δ) and midgap voltage (Δ) hysteresis after high-temperature positive and negative bias stress demonstrated that incorporating a thin AlO layer at the interface is the key factor in enhancing the stability of and midgap voltage .
本研究提出了一种在碳化硅（SiC）上生长栅氧化层的创新方法，即在沉积的AlO层上制备氧化硅（SiO），从而获得高质量的栅氧化层。通过原子层沉积（ALD）沉积一层薄的AlO钝化层，随后进行Si沉积和再氧化以制造MOS结构。系统地研究了不同ALD生长周期对MOS电容器的界面化学成分、陷阱密度、击穿特性和偏置应力稳定性的影响。X射线光电子能谱（XPS）分析表明，具有10个生长周期的ALD AlO钝化层有效地抑制了Si-OC键比例的形成。此外，具有10个ALD生长周期的SiO/AlO/SiC栅堆叠表现出最佳的电学性能，包括最小界面态密度（）值为3×10 cm eV以及击穿场强（）为10.9 MV/cm。我们还系统地分析了电容器在室温和高温下的偏置应力稳定性。对高温正负偏置应力后的平带电压（Δ）和带隙中点电压（Δ）滞后现象的分析表明，在界面处引入薄的AlO层是提高和带隙中点电压稳定性的关键因素。
