Abstract: There are several phenomena where the properties of vacancies and self-interstitials in silicon are manifested in straightforward ways. These include the formation of grown-in microdefects, the diffusion of metals (such as Au, Zn), self-diffusion and the installation of vacancy depth profiles in wafers by Rapid Thermal Annealing. Combining features extracted from the analysis of these phenomena, it is possible to define the diffusivities and equilibrium concentrations of the intrinsic point defects. Their diffusivities are remarkably high, and have weak temperature dependence. Their equilibrium concentrations are very low, and have strong temperature dependence.
Abstract: Thermal treatments to enhance precipitation like RTA, ramp anneal and argon anneal were performed on low oxygen 300 mm wafers without vacancy or interstitial agglomerates (“so called” defect-free material). Best results were achieved using high temperature argon anneal leading to a homogenous BMD and denuded zone formation. Furthermore the getter efficiency was positively tested by intentional Ni-contamination. Concepts to overcome the slip danger like improved support geometries and nitrogen codoping were also evaluated and are seen to be beneficial.
Abstract: Nitrogen doping of CZ silicon results in an early formation of large precipitate nuclei during crystal cooling, which are stable at 900°C. These are prone to develop stacking faults and high densities of defects inside defect denuded zones of CZ silicon wafers. Simultaneous doping of FZ silicon with nitrogen and oxygen results in two main stages of precipitate nucleation during crystal cooling, an enhanced nucleation around 800°C, which is nitrogen induced, and a second enhancement around 600°C, which depends on the concentration of residual oxygen on interstitial sites. A combined technique of ramping with 1K/min from 500-1000°C with a final anneal at 1000°C for 2h and lateral BMD measurement by SIRM provides a possibility to delineate v/G on nitrogen-doped silicon wafers. Surface segregation of nitrogen and oxygen during out-diffusion can explain the enhanced BMD formation in about 105m depth and the suppressed BMD formation in about 405m depth below the surface. The precipitate growth is enhanced in regions where nitrogen is filled up again after a preceding out-diffusion.
Abstract: In this paper, we present a study on the contribution of silicon nanocrystals to the electrical transport characteristics of large (100 m x 100 m) and small (100 nm x 100 nm) metaloxide- semiconductor (MOS) capacitors at room temperature. A layer of silicon nanocrystals is synthesized within the oxide of these capacitors by ultra-low energy ion implantation and annealing. Several features including negative differential resistance (NDR), sharp current peaks and random telegraph signal (RTS) are demonstrated in the current-voltage and current-time characteristics of these capacitors. These features have been associated to charge storage in silicon nanocrystals and to the resulting Coulomb interaction between the stored charges and the tunneling current. Clear transition from a continuous response of large capacitors to a discrete response of small capacitors reveals the quantized nature of the charge storage phenomenon in these nanocrystalline dots. The effect of the nanocrystal density from nearly continuous layer to isolated nanodots is also presented.
Abstract: Nanocrystals have attracted considerable attention in recent years because of their potential applications as a light source in Si technology. From theory Ge nanocrystals are expected to have better luminescence properties than Si nanocrystals. In this study we have compared Ge nanocrystals produced both in PE-CVD deposited and magnetron sputtered SiO2 doped with Ge during deposition to concentrations between 3-9 at.%, followed by high temperature treatment at temperatures between 600 and 1100°C. The nanocrystals were structurally characterized by Rutherford backscattering spectrometry (RBS), transmission electron microscopy (TEM) and electron paramagnetic resonance (EPR). The interface of the nanocrystals was passivated by use of alnealing, while the effect of the passivation was monitored by photoluminescence (PL)
Abstract: The properties of Si and Ge nanocrystals with uniformly strained Si-Si and Ge-Ge bonds have been studied. The strained Si and Ge nanocrystals were produced by the implantation of Ge+ or Si+ ions in thermally grown SiO2 films subsequently annealed under hydrostatic pressure ranging from 1 bar to 12 kbar. Correlation between the formation of the hydrostatically strained nanocrystals and the features of the photoluminescence spectra has been observed. The obtained results are discussed in terms of broadening energy gap between the levels of electron states of the hydrostatically strained nanocrystals. This effect brings about direct radiative recombination.
Abstract: The aim of this work is to study the physical obstacles introduced by the use of high-k MOSFETs structures and discuss basic problems associated with high-k candidates currently investigated such as low carrier mobility and parasitic interfacial layers and to present other ways to reduce the undesirable secondary effects when one replaces silicon with a high dielectric oxyde (high-k). We will show that use of the nitride allows reducing the effects of the interfacial layers with an acceptable reduction rate of mobility.
Abstract: The laser assisted formation of silicon nanocrystals in SiNx films deposited on quartz and silicon substrates is studied. The Raman spectroscopy revealed creation of the Si cluster and crystallite after excimer laser treatments. Photoluminescence signal from the samples was detected at room temperatures. I-V and C-V measurements were carried out to examine carries transfer through dielectrics film as well as recharging of electronics states.