Improvements on the Interfacial Properties of High-k/Ge MIS Structures by Inserting a La₂O₃ Passivation Layer

• Published in: Materials Vol. 11; no. 11; p. 2333
• Main Authors: Zhao, Lu, Liu, Hongxia, Wang, Xing, Wang, Yongte, Wang, Shulong
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 20.11.2018; MDPI
• Subjects: Aluminum oxide; Annealing; atomic layer deposition; Catalytic oxidation; CMOS; Current leakage; Defects; Desorption; Electric fields; Gates; Ge-based MIS; Germanium; Germanium oxides; Interfacial properties; Interlayers; Lanthanum oxides; Leakage current; Letter; MIS (semiconductors); Passivity; Spectrum analysis; surface passivation; Thin films; United States > US; Ge-based MIS; surface passivation; atomic layer deposition; interfacial properties
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma11112333

In this paper, the impact of La₂O₃ passivation layers on the interfacial properties of Ge-based metal-insulator-semiconductor (MIS) structures was investigated. It was proven that the formation of a thermodynamically stable LaGeO component by incorporating a La₂O₃ interlayer could effectively suppress desorption of the interfacial layer from GeO₂ to volatile GeO. The suppression of GeO desorption contributed to the decrease in oxide trapped charges and interfacial traps in the bulk of the gate insulator, or the nearby interfacial regions in the Al₂O₃/La₂O₃/Ge structure. Consequently, the hysteretic behavior of the dual-swept capacitance-voltage ( - ) curves and the frequency dispersion of multi-frequency - curves were remarkably weakened. Besides, more than one order of magnitude decrease in the gate leakage current density, and higher insulator breakdown electric field were obtained after inserting a La₂O₃ passivation layer.