Papers by Author: Chris I. Harris

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Authors: T. Paskova, E. Valcheva, Ivan G. Ivanov, Rositza Yakimova, Susan Savage, Nils Nordell, Chris I. Harris
Authors: Per Åke Nilsson, A.M. Saroukhan, J.O. Svedberg, Andrey O. Konstantinov, S. Karlsson, C. Adås, U. Gustafsson, Chris I. Harris, Niklas Rorsman, Joakim Eriksson, Herbert Zirath
Authors: Kent Bertilsson, Chris I. Harris
Abstract: Both unipolar and injection SiC devices can be used for high voltage switching applications; it is not determined, however, for which applications one approach is preferred over the other. In this paper, simulation studies are used to compare the suitability of unipolar devices, in this case a JFET (Junction Field Effect Transistor) against an equivalent FCD (Field Controlled Diode) configuration up to very high voltages. The calculations are performed in a finite element approach, with commercial drift-diffusion software. Numerous drift layers have been simulated in a Monte-Carlo approach to ensure that the optimal design of the drift layers for different breakdown is used. In a static case, purely conductive losses in the drift layer in both unipolar and injection configuration are compared. Additionally the total losses are studied and compared in switched applications for different switching frequencies and current levels.
Authors: Carl Mikael Zetterling, Mikael Östling, Chris I. Harris, Nils Nordell, K. Wongchotigul, Michael G. Spencer
Authors: Mietek Bakowski, Per Ericsson, Chris I. Harris, Andrey O. Konstantinov, Susan Savage, Adolf Schöner
Authors: E. Valcheva, T. Paskova, I.S. Ivanov, Rositza Yakimova, Qamar-ul Wahab, Susan Savage, Nils Nordell, Chris I. Harris
Authors: Andrey O. Konstantinov, Qamar-ul Wahab, Christer Hallin, Chris I. Harris, Béla Pécz
Authors: Andrey O. Konstantinov, J.O. Svedberg, I.C. Ray, Chris I. Harris, Christer Hallin, B.O. Larsson
Abstract: High power high efficiency silicon carbide RF MESFETs are fabricated using a novel structure utilizing lateral epitaxy. The MESFET employs buried p-type depletion stoppers grown by lateral epitaxy with subsequent planarization. The depletion stopper is epitaxially overgrown by the channel layer. The depletion stopper suppresses short channel effects and increases the operation voltage and the RF signal gain at high voltage operation. High breakdown voltages of over 200 Volts are achieved for single-cell components, however large-area transistors are limited to around 150 Volts. Single-cell components measured on-wafer demonstrate an Ft of 10 GHz and high unilateral gain. Packaged 6-mm RF transistors in amplifier circuits feature a saturated power of 20 W and a P1dB of 15W with a linear gain of over 16 dB at Vdd of 60 V for 2.25 GHz operation. Maximum drain efficiency is 56% for class AB operation, 48% at 1 dB compression point and 72% for class C at 2.25 GHz.
Authors: Andrey O. Konstantinov, Chris I. Harris, I.C. Ray
Abstract: High impedance silicon carbide power RF transistors are reported, which use the technology of Lateral Epitaxy Metal-Semiconductor FET (LEMES). The LEMES transistor utilizes a heavily doped buried depletion stopper to increase output impedance and breakdown voltage and to eliminate undesirable hot-carrier trapping effects. A power density of 2-3 W/mm at 2 GHz is routinely achieved resulting in a total output power of 10W for packaged components. The value of input and output impedance is around 50 Ohms for a frequency of around 2 GHz.
Authors: Susan Savage, Andrey O. Konstantinov, A.M. Saroukhan, Chris I. Harris
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