La 2 O 3 films are obtained by annealing in vacuum La(OH)3 layers produced upon air exposure of La2O3 layers grown using atomic layer deposition. Sample thickness determines whether hexagonal or cubic La2O3 form. The observed infrared active phonon mode with minimum frequency for hexagonal La2O3 films is located at 198cm−1, in good agreement with the first principles calculations, and at a lower frequency than the corresponding mode for cubic La2O3 is at 235cm−1. Accordingly, electrical measurements reveal a dielectric constant around 27 for hexagonal La2O3 films, significantly higher than the one around 17 derived for cubic La2O3 layers.

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La-doped ZrO2 thin films grown by O3-based atomic layer deposition directly on Ge(100) exhibit a dielectric constant of 29. Upon annealing in N2 at 400 °C, a high κ value >40 is extracted for film thickness below 15 nm. Compositional depth profiling allows to correlate this observation with a remarkable Ge interdiffusion from the substrate which is consistent with the stabilization of the tetragonal ZrO2 phase. Ge interaction with the oxide stack and the formation of a germanate-like interfacial region, which acts as an electrical passivation for the Ge surface, are also investigated.

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The fabrication of future nanoscale semiconductor devices calls for precise placement of dopant atoms into their crystal lattice. Monolayer doping combined with a conventional spike annealing method provides a bottom-up approach potentially viable for large scale production. While the diffusion of the dopant was demonstrated at the start of the method, more sophisticated techniques are required in order to understand the diffusion, at the near surface, of P and contaminants such as C and O carried by the precursor, not readily accessible to direct time-of-flight secondary ion mass spectrometry measurements. By employing atom probe tomography, we report on the behavior of dopant and contaminants introduced by the molecular monolayer doping method into the first nanometers. The unwanted diffusion of C and O-related molecules is revealed and it is shown that for C and O it is limited to the first monolayers, where Si-C bonding formation is also observed, irrespective of the spike annealing temperature. From the perspective of large scale employment, our results suggest the benefits of adding a further process to the monolayer doping combined with spike annealing method, which consists of removing a sacrificial Si layer to eliminate contaminants.