rodwell_ijhses_final - International Journal of High Speed...

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International Journal of High Speed Electronics and Systems f c World Scienti¯c Publishing Company Scaling of InGaAs/InAlAs HBTs for High Speed Mixed-Signal and mm-Wave ICs. M.J.W. Rodwell, M. Urteaga, Y. Betser ¤ , T. Mathew, P. Krishnan, D. Scott, S. Jaganathan D. Mensa, J. Guthrie y ,R .Pu l le la z ,Q .Lee x ,B .Agarwa l { ,U .Bhattacharya k ,S .Long Department of Electrical and Computer Engineering, University of California Santa Barbara, CA 93106, U.S.A. and S .C .Mart in .P .Sm ith ¤¤ NASA Jet Propulsion Labs, California Institute of Technology Pasadena, CA , USA Received Revised Accepted High bandwidths are obtained with heterojunction bipolar transistors by thinning the base and collector layers, increasing emitter current density, decreasing emitter contact resistivity, and reducing the emitter and collector junction widths. In mesa HBTs, minimum dimensions required for the base contact impose a minimum width for the collector junction, frustrating device scaling. Narrow collector junctions can be obtained by using substrate transfer processes, or {if contact resistivity is greatly reduced { by reducing the width of the base Ohmic contacts in a mesa structure. HBTs with submicron collector junctions exhibit extremely high f max and high gains in mm-wave ICs. Logic gate delays are primarily set by depletion-layer charging times, and neither f ¿ nor f max is indicative of logic speed. For high speed logic, epitaxial layers must be thinned, emitter and collector junction widths reduced, current density increased, and emitter parasitic resistance decreased. Transferred-substrate HBTs have obtained 21 dB unilateral power gain at 100 GHz. If extrapolated at -20 dB/decade, the power gain cuto® frequency f max is 1.1 THz. Transferred-substrate HBTs have obtained 295 GHz f ¿ .D emon s t ra t edIC s include lumped and distributed ampli¯ers with bandwidths to 85 GHz, 66 GHz master- slave °ip-°ops, and 18 GHz clock rate ¢ ¡ §ADCs . 1. Introduction Research in wide bandwidth heterojunction bipolar transistors (HBTs) 12 is driven by applications in high-frequency communications and radar. In optical ¯ber com- munications, integrated circuits for 40 Gb/s transmission are now in development ¤ Y. Betser is now with Anadigics Corp., Israel. y J. Guthrie is now with Nortel Networks, Inc. z D. Mensa, R. Pullela, and S. Jaganathan are now with Gtran, Inc x Q. Lee is now with Lucent Technologies { B. Agarwal is now with Conexant Corp. k U. Bhattacharya is now with Intel Corp. ¤¤ R. P. Smith is now with Cree Research, Inc. 1
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2 International Journal of High Speed Electronics and Systems 5 , 6 . Emergence of 160 Gb/s transmission equipment in the near future must rely on a timely and substantial improvement in the bandwidth of semiconductor elec- tronics. 160 Gb/s ¯ber transmission will require ampli¯ers with °at gain and linear phase over a » DC-110 GHz bandwidth and master-slave latches 3 (usedindecision circuits, multiplexers, and phase-lock loops) operable at 80 GHz or 160 GHz clock frequency.
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This note was uploaded on 08/06/2008 for the course ECE 145 taught by Professor Rodwell during the Fall '07 term at UCSB.

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rodwell_ijhses_final - International Journal of High Speed...

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