Search

In this work ultrathin strained silicon layers grown on relaxed Si0.9Ge0.1 substrates were oxidized under high thermal budget conditions in N2O ambient at 800 °C. The results indicate that the density of interface traps depends on the extent of the oxidation process. If the strained Si layer is totally consumed the density of interface traps reduces to almost half the value as compared to the case where a part of the strained Si layer still remains. The results indicate that the two existing interfaces of the strained Si layer, the SiO2/strained-Si and the strained-Si/Si0.9Ge0.1, contribute in parallel to the measured interface trap density. In addition, the buried strained-Si/Si0.9Ge0.1 interface constitutes a major source of the observed high density of interface traps. [ABSTRACT FROM AUTHOR]

Abstract: In this work, we investigate the implantation and diffusion of phosphorous (P) in germanium (Ge). Ge wafers were implanted at two different doses (5×1013 and 1015 cm−2) and a range of energies (30, 50 and 150keV). Part of the wafers was covered with a 40nm silicon dioxide (SiO2) and an 80nm silicon nitride (Si3N4) capping layer while the rest remained uncovered. Subsequently, the samples were furnace-annealed in an inert ambient (N2) at 500°C and a range of annealing times (30min to 5h). The experimental concentration profiles were obtained by secondary ion mass spectroscopy (SIMS). In the case of uncovered samples, substrate evaporation and significant phosphorous dose loss was observed, depending on the implantation and annealing conditions. At the lower implant dose, there is insignificant diffusion of phosphorous atoms in Ge, whereas at the higher implant dose, phosphorous exhibits a box profile consistent with previous experimental studies. [Copyright &y& Elsevier]

In this work, the surface damage induced in ion-implanted (100) Ge after extended (20 ms) flash lamp annealing (FLA) at 800–850 °C is investigated and discussed using combined results from scanning electron microscopy, transmission electron microscopy and atomic force microscopy. The induced surface damage has a variety of morphologies including shallow semi-spherical craters, large rectangular-base pyramids with protrusions, and inverted hollow square-base pyramids. The dominant defect morphology depends on the implanted species, the implantation conditions, the flash lamp annealing temperature, as well as on the capping layer used for the Ge surface protection. These results are interpreted using and adapting models developed to describe similar phenomena that take place during flash lamp annealing in Si. From a technological point of view, the most important outcome of this study is that nitrogen co-implantation enhances significantly the robustness of the Ge surface layer, as revealed by the suppression of the induced damage in all cases. Nitrogen co-implants appear to extend the flash lamp annealing thermal budget envelope, which could be useful to achieve a higher level of donor activation in Ge. [ABSTRACT FROM AUTHOR]

A sheet of spherical, well-separated, crystalline Ge nanodots embedded in SiO[SUB2] on top of a p-(001)Si wafer was fabricated by molecular beam epitaxy (MBE) combined with rapid thermal processing and characterized structurally and electrically. The average size of the Ge nanodots was estimated to be 4.5 nm with an average aerial density of 3X10[SUP11]cm[SUP-2], situated at 4.4 nm in average away from the Si/SiO[SUB2] (interface. Significant charge storage effects were observed through capacitance-voltage measurements of metal-oxide-semiconductor capacitors. [ABSTRACT FROM AUTHOR]