A selective CVD tungsten-strapped polysilicon local interconnectiontechnology

A local interconnection technology utilizing polysilicon strapped with selective-chemical-vapor-deposited (CVD) tungsten has been developed. Both n- and p-channel MOS transistors have been successfully fabricated using this technology. Tungsten deposited on polysilicon is an attractive gate shunt and local interconnection material because of its low resistivity, immunity to dopant segregation and diffusion, and resistance to electromigration. A potential problem of this technology is the excessive diode leakage current associated with strapping shallow source/drain diodes with tungsten. The leakage is attributed to defects induced by the heavy source/drain implant, which can be effectively eliminated with a proper annealing procedure     

Controlled oxygen incorporation in indium gallium arsenide and indium phosphide grown by metalorganic vapor phase epitaxy

The defect engineering in metalorganic vapor phase epitaxy In_xGa_1-xAs and InP by controlled oxygen doping using diethyl aluminum ethoxide (DEALO) was developed in this study. DEALO doping has led to the incorporation of Al and O, and the compensation of shallow Si donors in In_xGa_1−xAs: Si with 0 ≤ x ≤ 0.25. With the same DEALO mole fraction during growth, the incorporation of Al and O was found to be independent of x, but the compensation of Si donors decreases with increasing In content. Deep level transient spectroscopy analysis on a series of In_xGa_1-xAs: Si. samples with 0 ≤ x ≤ 0.18 revealed that oxygen incorporation led to a set of deep levels, similar to those found in DEALO doped GaAs. As the In composition was increased, one or more of these deep levels became resonant with the conduction band and led to a high electron concentration in oxygen doped In_0.53Ga_0.47As. Low temperature photoluminescence emission measurements at 12K on the same set of samples revealed the quenching of the near-band edge peak, and the appearance of new oxygen-induced emission features. DEALO doping in InP has also led to the incorporation of Al and O, and the compensation of Si donors due to oxygen-induced multiple deep levels.     

Distributed channel assignment strategies using coexistenceetiquettes for land based radio environment

The performance of two distributed channel assignment algorithms which use coexistence etiquettes for point to point links are considered by the authors. It has been found that selecting channels prior to transmission at the transmitter as opposed to the receiver, supports greater offered traffic with the additional advantage of a less complex protocol     

Monolithically integrated laser/rear-facet monitor arrays withV-groove for passive optical fiber alignment

An InGaAsP/InP laser monolithically integrated with a rear facet monitor and a fiber V-groove has been demonstrated for the first time. The integrated device incorporates an etched-facet laser fabricated using an in situ, multistep, reactive ion etch process. The integrated V-groove, which is etched directly into the InP substrate, is designed to enable passive alignment of an optical fiber to the active region of the laser. Passive coupling efficiencies of 18% and 8% have been obtained using cleaved multimode and single mode fibers, respectively. Responsivities of the rear facet monitor were as high as 0.49 A/W     

Extending trouble ticket systems to fault diagnostics

Network management in large heterogeneous communication environments requires the incorporation of more advanced tools than are currently available, especially in the area of fault management. By providing an informational infrastructure for documenting network behavior and maintenance activities, TTSs (trouble ticket systems) have provided some relief for the fault management problem. Researchers have recognized TTSs as a means for realizing more advanced functions in network management platforms to effect automatic trouble ticket generation, fault diagnostics, and the correlation of multiple views network problems and behavior. The authors describe current research trends towards understanding and implementing these advanced functions in a TTS framework     

Services and applications: requirements and realizations in theUMTS era

The ACTS program is moving the results of the R&D of the parent RACE program nearer to realization through technology and user trials. Particularly in the mobile domain of ACTS, several projects have been investigating the user dimension in the context of the third-generation Universal Mobile Telecommunications Service. Results so far suggest many opportunities to broaden participation, exploit the inherent benefits of the mobile environment, and take advantage of the enormous improvements in wireless communications to realize the potential of global multimedia mobility. This article considers the needs of users for mobile multimedia applications and the consequences of those needs on the equipment, supporting services and teleservices, and communications bearers     

Two-dimensional FDTD analysis of a pulsed microwave confocal systemfor breast cancer detection: fixed-focus and antenna-array sensors

A novel focused active microwave system is investigated for detecting tumors in the breast. In contrast to X-ray and ultrasound modalities, the method reviewed here exploits the breast-tissue physical properties unique to the microwave spectrum, namely, the translucent nature of normal breast tissues and the high dielectric contrast between malignant tumors and surrounding lesion-free normal breast tissues. The system uses a pulsed confocal technique and time-gating to enhance the detection of tumors while suppressing the effects of tissue heterogeneity and absorption. Using published data for the dielectric properties of normal breast tissues and malignant tumors, the authors have conducted a two-dimensional (2-D) finite-difference time-domain (FDTD) computational electromagnetics analysis of the system. The FDTD simulations showed that tumors as small as 2 mm in diameter could be robustly detected in the presence of the background clutter generated by the heterogeneity of the surrounding normal tissue. Lateral spatial resolution of the tumor location was found to be about 0.5 cm