Interface engineering of Ge using thulium oxide: Band line-up study
2013 (English)In: Microelectronic Engineering, ISSN 0167-9317, Vol. 109, 204-207 p.Article in journal (Refereed) Published
This paper investigates the band line-up and optical properties (dielectric function) of Tm2O3/Ge gate stacks deposited by atomic layer deposition. X-ray photoelectron spectroscopy has been performed to ascertain the shallow core levels (Ge3d and Tm4d) in ultra-thin and bulk Tm2O3/Ge stacks as well as valence band maxima in Ge and bulk Tm2O3. The valence band offset of Tm2O3/Ge has been found to be 2.95 +/- 0.08 eV. Vacuum ultra violet variable angle spectroscopic ellipsometry studies reveal the indirect band gap nature of Tm2O3, with the value extracted from the Tauc method of 5.3 +/- 0.1 eV. A distinct absorption feature is observed at similar to 3.2 eV below the band gap of Tm2O3, and clearly distinguished from the Si and Ge critical points. A dielectric constant of 14 to 15 has been derived from the electrical measurements on 5 nm Tm2O3/epi Ge/Si gate stacks. The band line-up study of Tm2O3/Ge implies an acceptable barrier for holes (2.95 eV) and electrons (greater than 1.7 eV) for Ge MOSFET engineering.
Place, publisher, year, edition, pages
Elsevier, 2013. Vol. 109, 204-207 p.
Thulium oxide, Valence band offset, Band gap
Engineering and Technology
IdentifiersURN: urn:nbn:se:kth:diva-125541DOI: 10.1016/j.mee.2013.03.160ISI: 000321229200054ScopusID: 2-s2.0-84876697515OAI: oai:DiVA.org:kth-125541DiVA: diva2:640257
QC 201308132013-08-132013-08-092013-08-13Bibliographically approved