Improving Three-Dimensional Semiconductor Modeling through Layout and Process Flow Analysis
Constructive Solid Geometry (CSG) is a solid modeling technique widely used for the design of semiconductor devices. With the simulation domain subdivision algorithm presented in this paper, the minimal number of solid modeling operations is required in order to build a three-dimensional (3D) device structure. The algorithm is based on a drawing method which combines information on photolithographic masks into a color raster. In this way, solid modeling operations are performed only once on regions having the same color.
Integrated BiCMOS process and circuit development using SPR
An integrated process development environment is described. Geometry information for process simulation is taken automatically from a commercial layout tool, and process step information exists in a high-level language databank. Doping information can be read by a device simulator, permitting SPICE (simulation program with IC emphasis)-like circuit simulation. This environment is presented in a BiCMOS development context.<<ETX>>
Venus: Evolution of the Upper Atmospheric Clouds
Abstract The large number of UV photographs taken by different observatories throughout the world are grouped for analysis at the IAU Planetary Photograph Center of Meudon Observatory. Three horizontal V, Y, or psi-shaped dark-hued cloud features are usually aligned along the equator and move 110 m s−1 westward in a planetary-wide rotation. The more intense and distinctly V-Shaped features last several weeks. The smaller scale cloud structures usually show significant changes after each successive rotation in 4 days around the planet. The average UV contrast is 32% but can fluctuate from disappearance to 37%. For periods of several years, the polar areas are sometimes covered by a white cloud. According to a set of photographs taken at Pic-du-Midi, this never occurred between 1962 and 1966 but has happened during 25% of the time for at least one pole since 1967, and only when the planet was in a given half of its orbit. These polar clouds are ephemeral and usually last several weeks or months; they evolve...