The relaxation process of strained silicon films on silicon-rich relaxed SiGe alloys has been studied. Experimental structures were grown via Molecular Beam Epitaxy (MBE) growth techniques and contain a strained silicon capping layer approximately 50 nm thick. The relaxed SiGe alloy compositions range from 0 to 30 at.% germanium. A 12 keV Si+ implant at a dose of 1×1015 atoms/cm2 was used to generate an amorphous layer ∼30 nm thick, which was confined within the strained silicon capping layer. Upon annealing at 500 °C, it was found that the solid phase epitaxial regrowth process of the amorphous silicon breaks down for high strain levels and regrowth related defects were observed in the regrown layer. In addition, high-resolution X-Ray diffraction results indicate a reduction in strain for the silicon capping layer. This study addresses the critical strain regime necessary for the breakdown of solid phase epitaxial recrystallization in silicon.

Using density functional theory (DFT) calculations within the generalized gradient approximation (GGA), we have investigated the structure, energies and diffusion behavior of Si defects including interstitial, vacancy, FFCD and divacancy in various charged states.

We implanted hydrogen in silicon with energies ranging from 500 keV to 2 MeV for implant depths varying from 6.1 to 48.4 μm according to TRIM (transport of ions in matter) 2003. After implantation, a 600 °C thermal annealing was applied to all samples. It is found that for depths lower than 9 μm there is no lift-off of a free-standing silicon layer; only a blistering phenomenon is seen. Increase in the implanted dose or thermal budget does not improve the situation. However, for depths ≥9 μm (9 - 50 μm in this study) thermal annealing results in effective detachment of ultra-thin free-standing layers. This technique hence provides high quality thin Si layers for semiconductor technology.

The contribution of the AC conductance on admittance spectroscopy measurements on Metal-Insulator-Semiconductor (MIS) devices allows the calculation of the interface traps density and the relevant time constant. Two equivalent model approaches can be applied in order to explain the experimental results. One model is the statistical model based on the Shockley- Read-Hall (S-R-H) recombination statistics and the other one is a model based on the quantum tunneling effect. Recent evidence suggest that the tunneling model can be equivalent to the statistical one if a continuum of states is also considered in the modeling, creating an extended tunneling model. In the present paper, a further investigation on the extended model is attempted. Admittance spectroscopy data were collected for various Insulator/Si combinations, such as SrTiO3 and BaTiO3 deposited on Si. Both the S-R-H based and the extended tunneling models were used to analyze the data. The results showed that the extended tunneling can model the conductance of the device successfully and can calculate the interface states density and the traps time constant.

High dose helium implantation followed by a suitable thermal treatment induces defects such as cavities and dislocations. Gettering efficiency of this technique for metallic impurities has been widely proved. Nevertheless, dopants, as well as point defects, interact with this defect layer. Due to the presence of vacancy type defects after helium implantation, boron diffusion can be largely influenced by such a buried layer. In this paper, we study the influence of helium induced defects on boron diffusion. The boron diffusion in presence of these defects has been analyzed as a function of different parameters such as distance between boron profile and defect layer and defect density. Our results demonstrate that the major impact known as boron enhanced diffusion can be partially or completely suppressed depending on parameters of experiments. Moreover, these results clarify the interaction of boron with extended He-induced defects.

Strained-Si based Field Effect Transistors (FETs) have enabled improvement of carrier transport in Metal Oxide Semiconductor (MOS)-based devices, both in the ON state of the device and in the sub-threshold region. This leads to devices with higher ratios of on-to-off current, improvements in the device sub-threshold slope, lower voltage operation, and carrier mobility enhancement. However, in order to understand the fundamental physics of these devices, it is important to address the stress conditions of the strained-Si channel layers after device processing, particularly after the ion-implantation process. In this work, we have studied Si+ self ion-implantation and thermally annealed strained-Si channel layers in n-MOSFETs. It has been observed that the density of defects in the strained-Si layer depends upon implant dose as well as thermal treatment. Using energy dispersive spectroscopy (EDS) spectra, it is found that Ge is present in the strained Si layer when analyzed after Si+ implantation and rapid thermal annealing. The presence of Ge in the strained Si channel layer causes relaxation of strain. This is verified by Convergent Beam Electron Diffraction (CBED) by measuring the lattice constant of the strained channel. It is concluded that electron mobility enhancements can be degraded in n- MOSFETs due to presence of both Ge up-diffusion and defects.