Rare earth oxides could represent a valuable alternative to ${\mathrm{SiO}}_2$ in complementary metal–oxide–semiconductor devices. ${\mathrm{Lu}}_2{\mathrm{O}}_3$ is proposed because of its predicted thermodynamical stability on silicon and large conduction band offset. We report on the growth by atomic-layer deposition of lutetium oxide films using the dimeric ${\left\{{\left[{\mathrm{C}}_5{\mathrm{H}}_4{(\mathrm{SiMe}}_3)\right]}_2\mathrm{LuCl}\right\}}_2$ complex, which has been synthesized for this purpose, and ${\mathrm{H}}_2\mathrm{O}$ . The films were found to be stoichiometric, with ${\mathrm{Lu}}_2{\mathrm{O}}_3$ composition, and amorphous. Annealing in nitrogen at $950°\mathrm{C}$ leads to crystallization in the cubic bixbyite structure. The dielectric constant of the as-grown ${\mathrm{Lu}}_2{\mathrm{O}}_3$ layers is $12\pm 1$ .

A comprehensive study of the biaxial strain-induced shift of the ${\text{Si}}_{1-x}{\text{Ge}}_x$ Raman active phonon modes is presented. High-resolution Raman measurements of ${\text{Si}}_{1-x}{\text{Ge}}_x/\text{Si}$ heterostructures have been compared to x-ray diffraction data. Our approach, unlike previous works, is effective to decouple and quantify separately the effect of strain and composition on the phonon frequencies, yielding an accurate determination of the phonon strain shift coefficients in the entire composition range. Our results show that the strain shift coefficients are independent of the composition, a result which is in good agreement with theoretical calculations, performed within the framework of valence force-field theory.

We present the development of a Raman spectroscopy technique for the measurement of the tensorial nature of stress in silicon on a micrometric scale. After the detailed description of the theoretical bases of the experiment, we measure the stress tensor of a silicon surface close to a scratch. Then, we apply this method to discern which models are suitable for the description of the stress tensor in shallow trench isolations for microelectronics.

Internal photoemission spectroscopy has been used to determine the band alignment in ${\mathrm{Lu}}_2{\mathrm{O}}_3$ based metal-oxide-semiconductor structures. The Si/${\mathrm{Lu}}_2{\mathrm{O}}_3$ interface conduction- and valence-band offsets were determined to be $2.1\pm 0.1$ and $2.6\pm 0.1\mathrm{eV}$ , respectively. The energy barrier for electrons at the Al/${\mathrm{Lu}}_2{\mathrm{O}}_3$ interface is $2.4\pm 0.1\mathrm{eV}$ . The value of the ${\mathrm{Lu}}_2{\mathrm{O}}_3$ transport band gap, obtained by photoconductivity measurements, was found to be $5.8\pm 0.1\mathrm{eV}$ . Optical absorption spectroscopy gave a value of $4.89\pm 0.02\mathrm{eV}$ for the ${\mathrm{Lu}}_2{\mathrm{O}}_3$ optical band gap.

We present a combined experimental and theoretical analysis of the dielectric and vibrational properties of crystalline lutetium oxide in its ground-state bixbyite structure. The vibrational dielectric function of ${\mathrm{L}\mathrm{u}}_2{\mathrm{O}}_3$ thin films grown by atomic-layer deposition was studied by infrared transmission and reflection-absorption spectroscopies, selectively accessing transverse and longitudinal optical frequencies. The static dielectric constant is extracted analyzing the infrared response. We also present first-principles density-functional linear-response calculations, which are in close agreement with experiment, and provide insight into the microscopic nature of vibrational spectra and dielectric properties.