Sister Mary Regina Donovan, S.S.J. (Nora Donovan)

Thin silicon dioxide layers (40-100 A) can be successfully produced by anodization of silicon in pure water. The resulting layers are very homogeneous and pinhole free. The monitoring of the SiO2 thickness is accurately achieved by simple coulometry. The electrical properties of the oxide layers and the associated Si/SiO2 interface have been investigated by forming metal-oxide-semiconductor (MOS) capacitors using the anodically grown oxide as the dielectric and aluminium or chromium as the metal. This investigation shows a low charge density at the Si/SiO2 interface (≤ 10 11 charges. cm-2) and an interface states density comparable to that obtained with thermally grown SiO2 (1011 cm -2eV-1). The dielectric breakdown occurs at high fields (11 to 14 MW . cm-1). These results show that there is no pollution during the electrolysis. Furthermore, the metal to oxide barrier heights remained high (2.5 to 2.8 eV) even for thin (44 A) SiO2 layers

First-Principles Study of the Band Gap Structure of Oxygen-Passivated Silicon Nanonets

A net-like nanostructure of silicon named silicon nanonet was designed and oxygen atoms were used to passivate the dangling bonds. First-principles calculation based on density functional theory with the generalized gradient approximation (GGA) were carried out to investigate the energy band gap structure of this special structure. The calculation results show that the indirect–direct band gap transition occurs when the nanonets are properly designed. This band gap transition is dominated by the passivation bonds, porosities as well as pore array distributions. It is also proved that Si–O–Si is an effective passivation bond which can change the band gap structure of the nanonets. These results provide another way to achieve a practical silicon-based light source

SiON based antireflective coating for 193nm lithography

International audienc

Small-angle X-ray scattering study of the microstructure of highly porous silicon

Small-Angle X-ray Scattering is well suited to the study of porous silicon microstructure since the pore radii range (2-10 nm) corresponds to the small-angle scattering range (1-100 nm). In all the studies realized till now, the porous silicon layers were always supported by the substrate. Recently, it has been possible to detach the porous silicon layer from the substrate. We performed small-angle X-ray scattering measurements, on such P-type samples, at a synchrotron radiation source. Close to the origin, the scattering pattern shows an anisotropic behaviour when titling the sample surface with respect to the X-ray beam. This anisotropy is different from the one observed previously in the case of P+ samples

Low-temperature solid phase epitaxy for integrating advanced source/drain metal-oxide-semiconductor structures

International audienceWe show that chemical vapor deposition using trisilane decomposition opens capabilities for the deposition of amorphous silicon on Si substrate at low temperature. Based on this behavior we developed a process including amorphous silicon deposition and crystallization. Transmission electron microscopy observations prove that solid phase epitaxy (SPE) occurs and produces monocrystalline layers, free of extended defects and compatible with complementary metal-oxide-semiconductor technology. We also show that during SPE films remain amorphous on oxidized areas while they transform into single crystal on Si. This process opens promising perspectives for the fabrication of advanced MOS structures