MIMC reliability and electrical behavior defined by a physical layer property of the dielectric

Metal–insulator–metal capacitor (MIMC) reliability and electrical properties are defined by the TDDB lifetime, breakdown voltage and leakage current. In this article, the correlation is determined between these electrical properties and the physical and chemical properties of the SiN dielectric layer. It is demonstrated how a SiN dielectrics with a high refractive index have high Si content and show an increased initial leakage current. However, contradictory to the high leakage current, these dielectrics also show high lifetimes. It is shown that SiN dielectrics with a high Si content contain high numbers of charge trapping centers. Over time, a high concentration of trapped charges is build up to such an extend that the local electric field over the dielectric is significantly decreased. This results in the observed reliability improvement of the dielectric. The final intrinsic quality and reliability of MIMC capacitors can therefore be determined by measurable physical properties of the MIMC dielectric at the time of the deposition of this layer.     

Routing in an AWG-Based Optical Packet Switch

For the next generation of the optical internet, focus is now moving from circuit switched networks, which occupy a wavelength continuously regardless of the demand at that time, towards optical packet/burst switching. By only occupying a wavelength when data is to be transmitted, a more efficient utilization of bandwidth in optical fibers is strived for. As bandwidth in fibers keeps increasing, the bottleneck of the optical network is now moving towards the switching node, since evolution of electronic routers cannot follow the speed of bandwidth increase. Thus a key component in these novel networks is the optical node. Through this node we want to switch traffic very fast and reliably, preferably transparent. Lack of efficient and practically realizable optical buffer, however, makes migration from electronic routers to optical routers a non-straightforward transition. In most optical nodes payload traffic can be switched transparently, whilst control information (e.g., in a header, on a control channel) is still converted to the electronic domain in every node, since optical processing is far from mature. In this paper we present a possible architecture for such a node, array waveguide gratings and all-optical tuneable wavelength converters. The concept of this switch is explained and the node is evaluated in terms of loss rate. We will see that an inherent problem of this switch is its internal blocking. This drawback can be greatly overcome by using an intelligent and efficient wavelength assignment algorithm within the node. Simulation of slotted operation will give some numerical results.     

Thickness variations during MOVPE growth on patterned substrates

Experiments have been carried out to investigate thickness variations between epitaxial layers grown on ridges or channels and the surrounding planar surface. Results show a remarkable variation in growth velocity, even for relatively wide channels and ridges. Using these findings, a novel laser/waveguide coupling technique, which uses a single epitaxial growth step, is proposed.     

Europeanist-programme roadmap for optical communications generated by theoptimist thematic network

On the basis of Europeanist project results in the field of photonics, theoptimist thematic network has produced a roadmap for optical communications. This work is described in the present article which provides scenarios for the evolution of the optical network in the coming 10 years. Predictable developments in optical components, sub-systems and systems and their consequences on the architecture and performances of the networks are analysed. Specific interest is focused on the various parts of the network structure namely the access, the metropolitan area, the wide area and the global networks. Technical documents elaborated by theoptimist consortium and minutes fromist workshops can be found on the website http://www.ist-optimist.org/.[1]. They constitute a main source for further information.     

Epitaxial lift-off GaAs LEDs to Si for fabrication of opto-electronic integrated circuits

The authors report, for the first time, the successful integration of GaAs LEDs on Si using the epitaxial lift-off technique. LEDs were processed after the transfer and could be aligned to features on the Si substrate. LED contacts were defined on both sides of the thin layer. Operation characteristics similar to those of LEDs grown on GaAs were observed. This realisation holds out interesting prospects in the fabrication of quasi-monolithic opto-electronic integrated circuits.<>