Influence Mechanism of Barium Interface Layer on the Interfacial Properties of n-Type 4H-SiC Metal-Oxide-Semiconductor Capacitors
Influence Mechanism of Barium Interface Layer on the Interfacial Properties of n-Type 4H-SiC Metal-Oxide-Semiconductor Capacitors
复制标题
钡界面层对n型4H-SiC金属氧化物半导体电容器界面性能的影响机制
DOI：
10.1002/pssb.202000269
复制
发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Zhang Yuming
中科院分区：
文献类型：
--
作者：
Bai Zhiqiang;Tang Xiaoyan;Zhang Yimeng;Jia Yifan;Jie Jiamin;Song Qingwen;Zhang Yuming
通过添加碱土金属界面层可以显著改善4 H-SiC/SiO2界面质量。为了研究碱土金属钡的钝化机理，建立了一个具有过渡层的超原电池模型。如第一性原理计算的结果所示，当在过渡层中引入Si <$Ba <$O或O <$Ba <$O结构时，带隙增加，态密度降低。制备了不同退火条件下的4 H-SiC/Ba界面层/SiO2电容器。X射线光电子能谱（XPS）结果表明，Ba在Ar气氛中5%O2退火后主要以BaO 2形式存在（对应于O <$Ba <$O结构），界面处的低价氧化物种类比Ar气氛中退火少。少量的Ba也与SiO2结合形成Si <$Ba <$O y化合物（对应于Si <$Ba <$O结构）。电容-电压测量结果验证了理论分析的正确性。分析了Ba钝化的物理机制，为提高SiC MOS结构器件的性能提供了理论依据。
The 4H‐SiC/SiO2interface quality can be significantly improved by adding an alkaline earth metal interface layer. To study the passivation mechanism of the alkaline earth metal barium (Ba), a supercell model with a transition layer is established. As shown in the results from first‐principles calculations, the bandgap increases and the density of states decreases when SiBaO or OBaO structures are introduced into the transition layer. 4H‐SiC/Ba interface layer/SiO2capacitors with different annealing conditions are fabricated. X‐ray photoelectron spectroscopy results show that Ba mainly exists in the form of BaO2(corresponding to the OBaO structure) after annealing in 5% O2in Ar atmosphere, and there are fewer types of suboxides in the interface than those annealed in Ar. A small amount of Ba also combines with SiO2to form SiBaxOycompounds (corresponding to the SiBaO structure). The correctness of the theoretical analysis is verified by capacitance–voltage measurements. The physical mechanism of Ba passivation is analyzed in this article, which helps to improve the performance of SiC metal–oxide–semiconductor (MOS) structure devices.