Raytheon

About: Raytheon is a company organization based out in Waltham, Massachusetts, United States. It is known for research contribution in the topics: Signal & Antenna (radio). The organization has 15290 authors who have published 18973 publications receiving 300052 citations.

Semiconductor structures having dual surface via holes

Abstract: A semiconductor structure having an active layer formed over a first surface of a substrate. The semiconductor structure includes an electrode formed over a first surface of the structure. A conductive layer is formed over a second surface of the substrate. A conductor section passes through the semiconductor structure between the electrode and the conductive layer. The conductor section includes two conductive elements, one having a first end connected to the electrode and a second end terminating in the semiconductor structure; and the other conductive element having a first end connected to the conductive layer and a second end connected to the second end of the first conductive element. The second end terminates at, or in, an etch resistant layer disposed in the semiconductor structure between the active layer and the substrate. The method for forming the conductive sections includes etching the second via hole from the second surface of the substrate until the etching reaches an etch resistant layer. The walls of the second via hole and exposed portions of the conductive material covering the walls of the first via hole are covered with an electrically conductive material.

Full-band simulation of indirect phonon assisted tunneling in a silicon tunnel diode with delta-doped contacts

Abstract: Full-band simulations of indirect, phonon assisted, interband tunneling are used to calculate the current–voltage response of a low-temperature molecular-beam-epitaxy-grown silicon tunnel diode with delta-doped contacts. Electron confinement in the contacts results in weak structure in the current–voltage characteristic. The structure is lost when finite lifetime effects are included. The approach uses the nonequilibrium Green function formalism in a second-neighbor sp3s* planar orbital basis.

Lubrication system with tolerance for reduced gravity

Abstract: A lubrication system includes an auxiliary lubricant tank 48 , a supply conduit 58 extending from a source of lubricant 26 to the auxiliary lubricant tank. A reduced-G bypass line 108 branches from the conduit and enters the auxiliary tank at a first elevation E 1 . The system also includes an auxiliary tank discharge conduit 116 , a portion of which resides within the tank. The resident portion has an opening 122 at least partially at a second elevation E 2 higher than the first elevation.

Western Pacific modulation of large phytoplankton blooms in the central and eastern equatorial Pacific

Abstract: [1] Satellite observations show that large-scale phytoplankton blooms (increases in chlorophyll) occurred in the equatorial Pacific in 1998, 2003, and 2005, following termination of the three most recent El Nino events. The occurrence of blooms following successive El Nino events cannot be explained by local enhancement of vertical nutrient flux, as evidenced by observations of equatorial winds, thermocline depth, and the depth and strength of the Equatorial Undercurrent (EUC, which supplies the limiting nutrient iron to the euphotic zone). However, near the peak of each El Nino event (late in 1997, 2002, and 2004), while the thermocline of the western equatorial Pacific was anomalously shallow, the flow of the New Guinea Coastal Undercurrent (NGCUC, which is the primary source of iron-enriched waters to the EUC) intensified, and its core shoaled from >200 m to ∼100 m depth. Analysis of NGCUC variability using a high-resolution, terrain-following three-dimensional ocean circulation model simulation indicates that as the NGCUC shoals and intensifies, it develops meanders and eddies that augment coupling of the New Guinea shelf and upper slope to the EUC. We hypothesize that these changes in NGCUC circulation during El Nino enhance iron transport from the New Guinea margin into the EUC and thereby trigger large-scale blooms when iron-enriched waters subsequently reach the euphotic zone along the equator. The threefold to fourfold chlorophyll increases over large regions, up to ∼5 × 105 km2, must have profound impacts on the equatorial ecosystem and biogeochemical cycles.

Heavy-ion broad-beam and microprobe studies of single-event upsets in 0.20-/spl mu/m SiGe heterojunction bipolar transistors and circuits

Abstract: Combining broad-beam circuit level single-event upset (SEU) response with heavy ion microprobe charge collection measurements on single silicon-germanium heterojunction bipolar transistors improves understanding of the charge collection mechanisms responsible for SEU response of digital SiGe HBT technology. This new understanding of the SEU mechanisms shows that the right rectangular parallel-piped model for the sensitive volume is not applicable to this technology. A new first-order physical model is proposed and calibrated with moderate success.