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).
An analytical model for the forward characteristics of gated p-i-n switches applied to lateral structures
This paper models the forward characteristics of high voltage p-i-n switches. The model is applied to the gated diode switch which is used in the subscriber line interface circuits of telecommunication systems. The p-shield around the cathode of the GDS, which is used for punchthrough protection, is shown to limit the injection efficiency of the cathode in linear devices. The resultant carrier distribution in the drift region is asymmetrical resulting in a large voltage drop. The model predicts that when the cathode efficiency is improved, even at the expense of the anode efficiency, the drift voltage and the drift resistance are reduced. Radial structures, with larger cathode areas and smaller anode areas than the linear structures, show an improved on resistance for competitive device areas. An optimum cathode to anode edge length ratio is obtainable to minimize the on resistance at a fixed current. While gated p-i-n structures are modeled in this paper, these principles are applicable to all lateral double injection devices.
Clozapine derived 2,3-dihydro-1H-1,4- and 1,5-benzodiazepines with D4 receptor selectivity: synthesis and biological testing.
Novel 4-arylpiperazin-1-yl-substituted 2,3-dihydro-1H-1,4- and 1H-1,5-benzodiazepines and their aza-analogues were synthesized as debenzoclozapine derivatives for evaluation as potential D4-ligands. While Ki values of some of the title compounds came within the range of clozapine, they showed an impressively greater selectivity over other dopamine receptor subtypes, especially D2. For the most promising compounds, intrinsic activity and binding properties to serotonin 5-HT1A and 5-HT2 were also determined.