Bonding and structure of ultrathin yttrium oxide films for Si field effect transistor gate dielectric applications

Abstract

Photoemission and ab initio theoretical study of interface and film formation during epitaxial growth and annealing of praseodymium oxide on Si(001) Soft x-ray photoelectron spectroscopy using synchrotron radiation has been employed to study the interface between Y 2 O 3 films and Si͑100͒. Y 2 O 3 films of ϳ8, ϳ15, and 65 Å were formed by plasma assisted chemical vapor deposition on HF-last Si͑100͒. With this deposition technique, SiO 2 forms at the interface and a kinetically limited silicate layer forms between the resulting SiO 2 deposited Y 2 O 3 . For 65 Å films, the Y 3d 5/2 binding energy was between 158.8 and 159.0 eV, 2.2-2.4 eV higher than the reported value of 156.6 eV for Y 2 O 3 . For 8 and 15 Å films, the Y 3d 5/2 binding energies were 159.6 and 158.9 eV, respectively. The relatively high binding energies are attributed to hydroxide incorporation in the film. For the ultrathin films, ϳ10 Å of SiO 2 was formed at the interface during or after the deposition. For the 8 Å film, no silicate is detectable whereas for the 15 Å film, an estimated 4 Å of silicate is present between the interfacial SiO 2 and Y 2 O 3 overlayer. Because this transition layer does not form in the 8 Å film, it is concluded that the mixing is kinetically limited. For the 8 Å film, the Si 2p 3/2 ͓SiO 2 ͔ binding energy was 3.65 eV relative to the substrate peak. For the 15 Å deposition, the Si 2p 3/2 ͓SiO 2 ͔ binding energy was 3.44 eV and the Si 2p 3/2 ͓silicate͔ binding energy was 2.65 eV relative to the substrate peak.

closo-Dodecaborate Intercalated Yttrium Hydroxide as a First Example of Boron Cluster Anion-Containing Layered Inorganic Substances

“…Y 3d photoelectron spectra were interpreted considering both NIST data and previously reported results. − Analysis of core-level Y 3d high-resolution spectra (Y 3d 3/2 and Y 3d 5/2 spin–orbit components) in the 154–164 eV region showed that a reliable difference in binding energy values for the Cl-LYH and B-LYH samples is observed (see Figure S8, Supporting Information). Y 3d core levels for closo -dodecaborate intercalated layered yttrium hydroxide shifted (ca.…”

Water assisted atomic layer deposition of yttrium oxide using tris(N,N′-diisopropyl-2-dimethylamido-guanidinato) yttrium(iii): process development, film characterization and functional properties

“…Before sputtering, the O 1s peak shows three components at BE positions of 529.0 eV (assigned to Y-O bonds), 531.6 eV (assigned to Y-OH bonds) and 533.5 eV (assigned to adsorbed water species). [28][29][30] The existence of Y-OH bonds and adsorbed water species is in accordance to the ALD process, which ended with a water pulse and purge and thus, reactive hydroxyls can remain on the surface (Fig. 3a).…”

“…A weak signal is also visible at around 153 eV, associated to the Si 2s peak of adsorbed silicon species (2.6 at% of Si was detected on the as-introduced sample), probably originating from adsorption of silicon grease during transfer of the sample to the spectrometer. 28,29,31 The C 1s peak reveals three different contributions at 284.7 eV (carbon, C-H, major), 285.9 eV (C-OH, minor) and 289.2 eV (O-C]O, minor) as depicted in Fig. S5, † attributed to adventitious carbon (the carbon amount in the sample as-introduced was 35.4 at%).…”

Effective reduction of trap density at the Y2O3/Ge interface by rigorous high-temperature oxygen annealing

“…Sometimes the shift of the Y 3d peak towards higher BE is attributed to an increased incorporation of OH-groups into the Y 2 O 3 film. 26,49 In our case, a stoichiometry of O:Y ¼ 1.43 for the as deposited films and O:Y ¼ 1.55 for the annealed Y 2 O 3 are measured (on Si) which means that also a strengthen build-in of OH groups during annealing can partly contribute to the observed peak shift. Almost no signal from sub-stoichiometric GeO x can be detected within our detection limit, and also for the annealed samples there is no evidence given for a metallic YGe phase with a reported shift in BE of $0.9 eV towards lower binding energies compared to the Ge 0 state.…”