How morphology determines the charge storage properties of Ge nanocrystals in HfO2

• Published in: Scripta materialia Vol. 113; pp. 135 - 138
• Main Authors: Slav, A., Palade, C., Lepadatu, A.M., Ciurea, M.L., Teodorescu, V.S., Lazanu, S., Maraloiu, A.V., Logofatu, C., Braic, M., Kiss, A.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.03.2016
• Subjects: Charge; Charge storage properties; Density; Evaporation; Germanium; Hafnium oxide; High-angle annular dark field (HAADF); High-resolution electron microscopy (HREM); Magnetron sputtering; Morphology; Nanocrystals; Nanostructured materials; X-ray photoelectron spectroscopy (XPS); Charge storage properties; High-resolution electron microscopy (HREM); Nanostructured materials; High-angle annular dark field (HAADF); X-ray photoelectron spectroscopy (XPS)
• ISSN: 1359-6462; 1872-8456
• DOI: 10.1016/j.scriptamat.2015.10.028

The strong correlation between morphology and charge storage properties of HfO2/Ge/HfO2/Si trilayer structures was evidenced. The morphology of structures deposited by magnetron sputtering and electron beam evaporation was tailored by rapid thermal annealing and investigated by transmission electron microscopy, Raman and X-ray photoelectron spectroscopies. The best hysteresis loops (capacitance–voltage characteristics) were obtained for trilayers with high density Ge nanocrystals located in the position of as-deposited Ge layer. The decrease of Ge nanocrystals density narrows the memory window, by spreading Ge atoms into HfO2 matrix (sputtered trilayers), or by Ge atoms expulsion toward HfO2 nanocrystals surface (evaporated trilayers). [Display omitted]