Atomic-layer deposited thulium oxide as a passivation layer on germanium



Mitrovic, IZ ORCID: 0000-0003-4816-8905, Hall, S ORCID: 0000-0001-8387-1036, Althobaiti, M, Hesp, D, Dhanak, V, Santoni, A, Weerakkody, D, Sedghi, N ORCID: 0000-0002-2004-6159, Chalker, P ORCID: 0000-0002-2295-6332, Henkel, C
et al (show 5 more authors) (2015) Atomic-layer deposited thulium oxide as a passivation layer on germanium. Journal of Applied Physics, 117 (21).

This is the latest version of this item.

[img] Text
JAP-Mitrovic et al-2015.pdf

Download (1MB)
[img] Text
Text-JAP-Mitrovic et al-Clean Copy-f.pdf

Download (219kB)
[img] Text
Figure1-JAP-Mitrovic et al.pdf

Download (74kB)
[img] Text
Figure2-JAP-Mitrovic et al.pdf

Download (35kB)
[img] Text
Figure3-JAP-Mitrovic et al.pdf

Download (81kB)
[img] Text
Figure4-JAP-Mitrovic et al.pdf

Download (811kB)

Abstract

A comprehensive study of atomic-layer deposited thulium oxide (Tm2O3) on germanium has been conducted using x-ray photoelectron spectroscopy (XPS), vacuum ultra-violet variable angle spectroscopic ellipsometry, high-resolution transmission electron microscopy (HRTEM), and electron energy-loss spectroscopy. The valence band offset is found to be 3.05 ± 0.2 eV for Tm2O3/p-Ge from the Tm 4d centroid and Ge 3p3/2 charge-corrected XPS core-level spectra taken at different sputtering times of a single bulk thulium oxide sample. A negligible downward band bending of ∼0.12 eV is observed during progressive differential charging of Tm 4d peaks. The optical band gap is estimated from the absorption edge and found to be 5.77 eV with an apparent Urbach tail signifying band gap tailing at ∼5.3 eV. The latter has been correlated to HRTEM and electron diffraction results corroborating the polycrystalline nature of the Tm2O3 films. The Tm2O3/Ge interface is found to be rather atomically abrupt with sub-nanometer thickness. In addition, the band line-up of reference GeO2/n-Ge stacks obtained by thermal oxidation has been discussed and derived. The observed low reactivity of thulium oxide on germanium as well as the high effective barriers for holes (∼3 eV) and electrons (∼2 eV) identify Tm2O3 as a strong contender for interfacial layer engineering in future generations of scaled high-κ gate stacks on Ge.

Item Type: Article
Subjects: Q Science > Q Science (General)
Q Science > QC Physics
Depositing User: Symplectic Admin
Date Deposited: 28 Apr 2016 13:30
Last Modified: 18 Jan 2021 12:10
DOI: 10.1063/1.4922121
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3000975

Available Versions of this Item