Monolithic high voltage gated diode crosspoint array IC
A new gated diode crosspoint integrated circuit has been developed for telephone switching system applications. Central to the design of this high voltage device has been the extensive use of numerical modeling techniques. Two-dimensional simulation of the individual dielectrically isolated components that comprise the switch array has led to an improvement in their electrical parameters together with size reduction for each of their geometries. Additional calculations dealing with the routing of interconnect metalization about the perimeter of components has indicated how such runners may encroach upon these elements without degrading their performance so that higher density circuitry could be assembled onto a chip. The resulting IC therefore realizes substantial advances over its predecessors, including: increased scale of integration (9 vs. 4 crosspoint pairs), more compact design (2.1 vs, 3.6mm2per crosspoint pair), higher OFF state minimum blocking voltage (600 vs. 530 volts), and reduced ON state incremental resistance (10 vs. 18 ohms).
High voltage integrated circuits for telecommunications
First, the recent progress in high voltage integrated circuits in Japan will be reviewed. Next, a family of high voltage integrated circuits with a blocking voltage of 350 V will be presented. These IC's are composed of thyristor switching elements, high voltage drivers and control circuits. The device is integrated on a dielectrically isolated substrate using a high voltage bipolar technology. In order to prevent deformation of the substrate during high temperature processing, a newly developed multi-polysilicon layer technology is applied to make the substrate. Both theoretical and experimental work has been done to reduce the electric field at the junction termination. On-state characteristics of the lateral thyristor have also been studied. Results from these studies will be presented.
Proliferative kidney disease: first reported outbreak in North America
Abstract. Proliferative kidney disease (PKD) was diagnosed in rainbow trout, Salmo gairdneri Richardson, at the Hagerman, Idaho, State Fish Hatchery. Wild fish from Riley Creek, one of the hatchery water supplies, were infected with PKD organisms. Clinical signs, gross pathology and histopathology of affected fish were typical of those reported for PKD in salmonids from European hatcheries. In addition to lesions normally seen, we observed a severe vasculitis and occlusion of renal and hepatic vessels. Ultrastructure of the PKD organism and possible inclusion body production sites are described. The disease outbreak was complicated by the presence of other infectious diseases. This is the first recorded outbreak of PKD in North America.