The effects of several key wafer processing conditions on submicron n-channel MOS transistor hot-carrier injection stability have been studied. Specifically, the interactions of gate oxide interface integrity, lightly...
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ISBN:
(纸本)0819410004
The effects of several key wafer processing conditions on submicron n-channel MOS transistor hot-carrier injection stability have been studied. Specifically, the interactions of gate oxide interface integrity, lightly doped drain spacer length and ion implant parameters, polycrystalline silicon gate oxidation sequence, and source-drain ion implant and anneal conditions have been examined. After wafer fabrication, packaged test transistors were subjected to accelerated hot-carrier stress conditions. Hot-carrier injection damage was assessed by measuring and comparing critical transistor DC parameters before and after stress. The relative impact of hot-carrier generation and trapping efficiency on the degradation of linear regime drain current was analyzed and compared for each set of process conditions. Additionally, circuit parameters were examined to assess the impact of process and device modifications on performance. Finally, an optimum set of processing conditions have been identified which insure maximum device stability without compromising device or circuit performance.
A Free Electron Maser is being designed for ECRH applications on future fusion devices. The FEM will have an output power of 1 MW, a central frequency of 200 GHz and will be adjustable over the complete frequency rang...
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ISBN:
(纸本)0819413925
A Free Electron Maser is being designed for ECRH applications on future fusion devices. The FEM will have an output power of 1 MW, a central frequency of 200 GHz and will be adjustable over the complete frequency range of 125 GHz to 250 GHz. The FEM operates with a thermionic electron gun. Fast tunability is achieved by variation of the voltage of the 2 Mev electrostatic accelerator. The undulator and mmw system are located in a terminal at a voltage of 2 Mv, inside a vessel filled with SF6 at a pressure of 7 bar. After interaction with the mm waves in the undulator, the energy of the electron beam will be recovered by means of a decelerator and a multi-stage depressed collector. The 'low emittance' electron beam will be completely straight to minimize current losses to less than 20 mA. This current is to be delivered by the 2 Mv dc accelerating voltage power supply. Simulations indicate that the overall efficiency will be over 50%. The interaction between the electron beam and the mm waves was simulated using both a 1-D, non-stationary code and a fully 3-D, stationary, amplifier code. Results with both codes, indicate that with a beam current of 12 A, an output power of 1 MW can be generated for all required frequencies with a beam energy ranging from 1.3 Mev (for 125 GHz) to 2 Mev (for 250 GHz).
The DC and low frequency noise characteristics of InGaAs/InP planar separate absorption, grading, charge, and multiplication (SAGCM) avalanche photodiode are reported. These devices have DC gains greater than 100 with...
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The DC and low frequency noise characteristics of InGaAs/InP planar separate absorption, grading, charge, and multiplication (SAGCM) avalanche photodiode are reported. These devices have DC gains greater than 100 with about 0.3 /spl mu/W input power and breakdown voltages v/sub br/ of 56 v. At 0.9 v/sub br/, the dark current is typically 10 nA for a 30-/spl mu/m-diameter active area device. The theoretical calculations of dark currents indicates that the primary dark currents come from generation-recombination and diffusion currents in both active and periphery regions. The breakdown voltage is in agreement with the calculation, which shows that the partial charge sheet does prevent the premature breakdown in the periphery region. The shot noise power is determined to be proportional to I/sup 2.7/, in agreement with theory. The lack of 1/f noise indicates the partial charge sheet is a good design to replace conventional guard ring design.< >
Typical conventional diesel engine designs are based on arrangements of single piston and cylinder sets placed sequentially either in-line or offset (''v'') along the crank-shaft. The development of ot...
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Typical conventional diesel engine designs are based on arrangements of single piston and cylinder sets placed sequentially either in-line or offset (''v'') along the crank-shaft. The development of other engines, such as the opposed piston type, has been motivated by potential advantages seen in such designs, which may not be viable in conventional in-line or v engine arrangements. Several alternatives to conventional engine design have been investigated in the past and some aspects of these designs have been utilized by engine manufacturers. The design and development of a proof-of-concept opposed piston diesel engine is summarized in this paper. An overview of opposed-piston engines is presented from early developments to currentdesigns. The engine developed in this work is a two stroke and uses four pistons, which move in two parallel cylinders that straddle a single crankshaft. A prechamber equipped with a single fuel injector connects the two cylinders, forming a single combustion chamber. The methodology of the engine development process is discussed along with details of component design. Experimental evaluations of the assembled proof-of-concept engine were used for determining feasibility of the design concept. An electric dynamometer was used to motor the engine and for loading purposes. The dynamometer is instrumented for monitoring both speed and torque. Engine parameters measured include air flow rate, fuel consumption rate, inlet air and exhaust temperatures, and instantaneous cylinder gas pressure as a function of crank position. The results of several testing runs are presented and discussed.
An introduction to current research in computer-aided design (CAD) and packaging for optoelectronic systems utilizing free space optical interconnects is presented. New CAD tools are presented that allow layout of mul...
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An introduction to current research in computer-aided design (CAD) and packaging for optoelectronic systems utilizing free space optical interconnects is presented. New CAD tools are presented that allow layout of multistage networks based on CGH fabrication limitations and the subsequent synthesis of the interconnect holograms. Recent work involving double-sided alignment of a single substrate as well as alignment techniques between two different substrates is discussed. Several packaged systems utilizing photorefractive crystals to minimize alignment problems are also presented.
The high resolution camera (HRC) is a set of microchannel plate based detectors designed to fly aboard the Advanced X-Ray Astrophysics Facility (AXAF), one of the `Great Observatories' under the auspices of NASA. ...
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ISBN:
(纸本)0819412589
The high resolution camera (HRC) is a set of microchannel plate based detectors designed to fly aboard the Advanced X-Ray Astrophysics Facility (AXAF), one of the `Great Observatories' under the auspices of NASA. The HRC is designed in two configurations, one for direct imaging and the other for reading out the spectrum of transmission gratings for high resolution spectroscopy. The currentdesign calls for different photocathodes: the imaging detector will have a CsI coating, and the spectroscopic detector will have KBr. Since the instrument is expected to perform over an extended period in space, we are interested in the long-term behavior of these coatings in vacuum. In this paper, we examine the current ROSAT experience from flight calibration observations with the HRI (the predecessor of HRC), and we outline plans for a test of the long-term stability of these coatings in vacuum and under nitrogen storage.
A GaAs MESFET large-signal equivalent circuit model with optical illumination effects has been developed. The model includes accurate representation of the drain current dependence on the operating voltages under diff...
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A GaAs MESFET large-signal equivalent circuit model with optical illumination effects has been developed. The model includes accurate representation of the drain current dependence on the operating voltages under different operational conditions. The model for the GaAs MESFET was implemented in PSPICE. Simulated results obtained are shown to compare well with the measured results, with a good fit to measured GaAs MESFET I-v characteristics over a wide bias voltage range and under both dark and illumination conditions. The RF response of the MESFET is also modeled and simulated. Such a circuit model is important in the design of optically controlled microwave circuits involving a GaAs MESFET as an optical interface.< >
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