In:
Surface and Interface Analysis, Wiley, Vol. 54, No. 8 ( 2022-08), p. 864-872
Abstract:
The thermal stability and material properties of HfO 2 thin films on Si substrates with and without H 2 O 2 wet chemical oxidation were investigated. The HfO 2 samples were deposited through plasma‐enhanced atomic layer deposition and subjected to thermal annealing. They were then examined using X‐ray diffraction, transmission electron microscopy, X‐ray photoelectron spectroscopy, reflection electron energy loss spectroscopy, and conductive atomic force microscopy. For the Si substrate without H 2 O 2 wet chemical oxidation, a native oxide (~1.8 nm) was formed on the substrate before HfO 2 deposition. After the annealing process at 600°C, the band gap ( E g ) of the HfO 2 films increased from 6.0 to 6.2 eV due to the diffusion of Si into HfO 2 . Furthermore, the conduction and valence band offsets (Δ E c and Δ E v , respectively) between HfO 2 and Si changed from 1.02 to 1.42 and 3.86 to 3.66 eV, respectively. After the H 2 O 2 wet oxidation of the Si substrate, a 1.5‐nm chemical oxide was formed instead of a native oxide. The band offset and E g values of HfO 2 were similar before and after 600°C annealing (Δ E v = 3.86 eV, Δ E c = 1.02 eV, and E g = 6.0 eV), implying the high thermal stability of the HfO 2 films. Accordingly, wet oxidation not only prevents diffusion from chemical oxide but also markedly improves the oxide leakage current, which is useful for developing highly efficient and thermally stable HfO 2 gate oxides in Si‐based integrated circuit devices.
Type of Medium:
Online Resource
ISSN:
0142-2421
,
1096-9918
Language:
English
Publisher:
Wiley
Publication Date:
2022
detail.hit.zdb_id:
2023881-2
Bookmarklink