Oxygen relocation during HfO₂ ALD on InAs

Abstract

Atomic layer deposition (ALD) is one of the backbones for today’s electronic device fabrication. A critical property of ALD is the layer-by-layer growth, which gives rise to the atomic-scale accuracy....

Atomic Hydrogen Annealing of Graphene on InAs Surfaces and Nanowires: Interface and Morphology Control for Optoelectronics and Quantum Technologies

“…The peak at lowest binding energy (green) corresponds to As in the bulk (As–In). The two components at 2.8 (blue) and 4.5 eV (pink) higher binding energy can be attributed to the As 3+ and As 5+ states of the native oxide as in As 2 O 3 and As 2 O 5 , respectively, in agreement with the literature. − The remaining peak, at a binding energy of 0.9 eV above that of the bulk component, can be attributed to As 0 , as it occurs in metallic As, As antisites, or other As defects . It should be noted that the same components can be found both on the graphene-covered and uncovered areas, while the absolute intensity of the As 3d signal is lower in the covered area, due to the attenuation by the graphene layer.…”

Role of Temperature, Pressure, and Surface Oxygen Migration in the Initial Atomic Layer Deposition of HfO2on Anatase TiO2(101)

“…Figure d). We have observed the ammonium species also in TiO 2 ALD from TDMA-Ti, but we did not in the ALD of HfO 2 from TDMA-Hf on InAs or on SiO 2 . ,, The C 1s:N 1s ratio is around 2, in agreement with the stoichiometry of the ligands. The Hf 4f line is found at 17.6 ± 0.1 eV binding energy.…”

“…If the water pressure is insufficient, then this process is favorable and leads to a net reaction without hydroxyl when all the ligands are removed. The mechanism is also observed in the ALD of HfO 2 on InAs …”

“…DMA – is also the only surface species that would be observed after the TDMA-Hf half-cycle if the only reaction that occurred was the physisorption of the metal precursor. While it is not clear that dissociative adsorption and physisorption can be distinguished from their N 1s signatures, the appearance of the Hf 4f XP spectra provides further information on the reaction path: The initial physisorbed state is characterized by a high Hf 4f binding energy of around 17.4–17.6 eV. , The physisorption is followed by an attack of the lone pair of a ligand nitrogen onto the surface, which causes a downshift of the Hf 4f binding energy by around 0.5 eV. The attack leaves the surface-adsorbed TDMA-Hf complex in an intact state, which, however, is more strongly bonded to the surface than the initially physisorbed molecule.…”

“…Specifically, for the case of HfO 2 ALD on oxidized InAs from the same precursors as discussed, here, we have found that the support provides oxygen to the surface already in the first ALD half-cycle, before the introduction of the second precursor, and that HfO 2 is formed already then. This active role of the support is behind the so-called self-cleaning process observed for the native oxides on III-V semiconductor surfaces. − While the effect is well known and documented, only few experimental and theoretical results have recognized the importance of this process on the formation of the first ALD layers . We have also shown that the surface chemical reaction of the initial oxide ALD may follow a completely different pathway from that in eq .…”