T.S. Elliott

Texas A&M University, College Station, Texas, United States

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Publications (7)2.23 Total impact

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    ABSTRACT: Yue began studying porous silicon-based vacuum microelectronic devices i n1990. Results from a device he dubbed the Oxidized Porous Silicon Field Emission Diode (OPSFED) showed that porous silicon (PS) offered an attractive alternative to standard field emission devices. Emission sites are reduced to near-atomic dimensions and site density is increased by six orders of magnitude. Yue, and later Madduri extracted electrons into the vacuum in a diode configuration, but no attempt to build a triode device had ever been successful. Using a novel metallization technique developed by Dr. R.C. Jaklevic et al. for use in STM imaging, the authors have successfully fabricated the first working PS-based vacuum microtriodes. Results are extremely encouraging. Collector currents up to 700 {micro}A were extracted across {approximately}3mm of vacuum with a pulsed DC gate bias of less than 20V. Simultaneous measurement of the gate current showed current densities to 700A/cm{sup 2}. Modulation of the emission to 5MH: was observed. Fowler-Nordheim plots show a slight curvature, as would be expected from extremely sharp emission tips, although it is stressed that the electroemissive mechanism is as yet unknown. Fowler-Nordheim plots for OPSFED`s made from the same material show an opposite curvature as predicted for emission from a large number of sites. Density of emitters approach a true two-dimensional limit, and many applications exist if the technology can be matured.
    07/1997;
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    ABSTRACT: In the effort to develop a high performance field emission cathode for application in microwave amplifiers, it is clear that the emitter structure should have a sharp emitter surface, a large emitter height, a small gate opening size, and a small emitter angle. We have developed a technique that fabricates knife‐edge field emission arrays (KEFEA) on (110) silicon wafers. KEFEA has an optimized structure meeting the requirements mentioned above. The emitter edge radius is about 250 Å or less, the emitter height is 8 μm, and the gate gap is ∼0.2 μm. Experiments have exhibited Fowler–Nordheim type field emission with gate‐to‐substrate bias voltage less than 50 V.
    Journal of vacuum science & technology. B, Microelectronics and nanometer structures: processing, measurement, and phenomena: an official journal of the American Vacuum Society 04/1994; · 1.36 Impact Factor
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    ABSTRACT: Field emitter devices are being developed for the gigatron, a high-efficiency, high frequency and high power microwave source. One approach being investigated is porous silicon, where a dense matrix of nanoscopic pores are galvanically etched into a silicon surface. In the present paper pore morphologies were used to characterize these materials. Using of scanning electron microscope (SEM) and transmission electron microscope (TEM) images of both N-type and P-type porous layers, it is found that pores propagate along the crystallographic direction, perpendicular to the surface of (100) silicon. Distinct morphologies were observed systematically near the surface, in the main bulk and near the bottom of N-type (100) silicon lift-off samples. It is seen that the pores are not cylindrical but exhibit more or less approximately square cross sections. X-ray diffraction spectra and electron diffraction patterns verified that bulk porous silicon is still a single crystal. In addition, a scanning tunnelling microscope (STM) and an atomic force microscope (AFM) were successfully applied to image the 40 Å gold film structure which was coated upon a cooled porous silicon layer. By associating the morphology study with the measured emitting current density of the oxidized porous silicon field emission triode (OPSFET), techniques for the surface treatment of porous silicon will be optimized
    01/1994;
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    ABSTRACT: Not Available
    Vacuum Microelectronics Conference, 1993., Proceedings of IEEE 6th International; 08/1993
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    ABSTRACT: The goal of developing a highly efficient microwave power source has led us to investigate new methods of electron field emission. One method presently under consideration involves the use of oxidized porous silicon thin films. We have used this technology to fabricate the first working field emission arrays from this substance. This approach reduces the diameter of an individual emitter to the nanometer scale. Tests of the first samples are encouraging, with extracted electron currents to nearly 1 mA resulting from less than 20 V of pulsed DC gate voltage. Modulated emission at 5 MHz was also observed. Development of a full-scale emission array capable of delivering an electron beam at 18 GHz of minimum density 100 A/cm<sup>2</sup> is in progress
    Particle Accelerator Conference, 1993., Proceedings of the 1993; 06/1993
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    ABSTRACT: Cathodes made of thin-film field emission arrays (FEA) have the advantages of high current density, pulsed emission, and low bias voltage operation. We have developed a technology to fabricate knife-edge field emission cathodes on (110) silicon wafers. The emitter geometry is optimized for efficient modulation at high frequency. The cathode fabrication progress and preliminary analysis of their applications in RF power sources are presented
    Particle Accelerator Conference, 1993., Proceedings of the 1993; 06/1993
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    ABSTRACT: We present results on the performance of Gas Microstrip Detectors on various substrates. These include a 300 μm anode-anode pitch pattern on Tempax borosilicate glass and ABS/copolyether, a 200 μm pattern on Upilex “S” polyimide, Texin 4215, Tedlar, ion-implanted Kapton, orientation-dependent etched flat-topped silicon (“knife-edge chamber”), and iron-vanadium glass, and a 100 μm pitch pattern on Upilex “S” and ion-implanted Kapton.
    Nuclear Physics B - Proceedings Supplements 05/1993; · 0.88 Impact Factor