GaAs layers grown by molecular beam epitaxy (MBE) at substrate temperatures between 200 and 300 °C were studied using transmission electron microscopy (TEM), x-ray diffraction, and electron paramagnetic resonance (EPR) techniques. High-resolution TEM cross-sectional images showed a high degree of crystalline perfection of these layers. For a layer grown at 200 °C and unannealed, x-ray diffraction revealed a 0.1% increase in the lattice parameter in comparison with bulk GaAs. For the same layer, EPR detected arsenic antisite defects with a concentration as high as 5×1018 cm−3. This is the first observation of antisite defects in MBE-grown GaAs. These results are related to off-stoichiometric, strongly As-rich growth, possible only at such low temperatures. These findings are of relevance to the specific electrical properties of low-temperature MBE-grown GaAs layers.

Disilicide of rare-earth metals (Dy, Er, Ho, and Gd) and Y have been formed by reacting the metallic film on both n- and p-type silicons at around 350 °C for Schottky-barrier height measurement using I-V technique. A passivation coating of W, or Pt, or both was used to prevent the rare earth from oxidation. Schottky-barrier heights of about 0.4 eV on n-Si and 0.7 eV on p-Si were determined.

Reactions between Si and thin films of rare-earth metals (Gd, Dy, Ho, Er, plus Y and La) in the temperature range of 275–900 °C have been studied by using x-ray diffraction and ion backscattering spectrometry. The disilicides of these metals are apparently the first phase to form, forming rapidly within a narrow temperature range (325–400 °C), and are stable up to 900 °C. The growth does not follow a layered growth mode.

Rutherford-backscattering spectrometry and x-ray-diffraction analysis have been used to investigate intermixing between thin metal films (Pt, Ni, and Hf) and silicon substrates as a result of inert-gas ion bombardment. Silicide phases (Pt2Si, Ni2Si, and HfSi) were observed near the interface as long as the ion range exceeds the film thickness. For a fixed dose, the silicide thickness increases with the atomic mass of both ion and metal and is greater for Pt2Si than HfSi. The growth of Pt2Si showed a square-root dependence on ion dose for Ar, Kr, and Xe ions. The phenomenon of ion-induced silicide formation is similar to formation resulting from thermal anneal until the whole metal film is consumed in the reaction, at which point a progressive intermixing to redistribute the metal into deeper regions of the sample occurred along with the disappearance of the structure diffraction patterns.