Michael S. Shur, Renssalaer Polytechnic Institute
Time: 7:00 PM, Wednesday, November 9th, 2005.
Place: Room 202, ECE Center, New Jersey Institute of Technology, Newark NJ.

Abstract

Wurtzite (hexagonal) symmetry makes the device physics of GaN/AlN/InN heterostructure field effect transistors (HFETs) to be quite different from that from more conventional GaAs/InAs/InP and Si based transistors. Spontaneous and piezoelectric polarizations at AlGaN/GaN or AlGaI nN/GaN lead to the formation of two-dimensional (2D) electron gas or 2D hole gas (depending on the surface polarities). These 2D electrons have a higher mobility compared to that for three dimensional electrons but a reduced peak velocity. In high electric fields, electron runaway effects and overshoot and ballistic effects play a dominant role. A field dependent penetration of the electron wave function from the device channel into the wide band gap barrier layer strongly affects the real space transfer and device breakdown voltage. Quantum well designs (e.g. incorporating an InGaN quantum well between the wide band gap AlGaN barrier layer and GaN buffer and thin AlN barrier) might be required to control this wave function penetration and the real space transfer. High electric field at the gate edges leads to the additional strain and hot electron effects causing the current collapse and gate lag. Optimized field plate and recessed gate designs (including the use of textured AlGaN for easily controlled etching) help solving this problem and improve the device reliability. Inverted HFET designs might result in reduced access resistance, a large current carrying capability, lower gate leakage and better thermal control. Large energy gap discontinuities at heterointerfaces allow for obtaining very large densities of 2D electrons (exceeding those at AlGaAs/GaAs heterointerfaces by a factor of 10 to 20) with a commensurate increase in the output power. Such large densities make the insulated gate design – MOSHFET - (with the dielectric layer separated from the active channel by the wide band gap barrier layer) practical, since one can tolerate a much higher density of the surface states. Large electron densities in the HFET channels also minimize the 1/f noise making it to be smaller than in doped GaN films. Insulated gate designs makes devices superior for DC and RF power applications.

Deep understanding of this new physics of GaN/AlN/InN HFETs is a prerequisite for the optimization of their design, improving their reliability and performance, and achieving a higher frequency operation.

Biography

Michael Shur received his MSEE (engineer) degree (with honors) from St. Petersburg Electrotechnical Institute, PhD in Physics and Mathematics and Doctor of Science in Physics and Mathematics degree, both from A. F. Ioffe Institute. He has held research or faculty positions at A.F. Ioffe Institute, Cornell, Oakland University, University of Minnesota, and University of Virginia, where he was John Money Professor of Electrical Engineering and served as Director of Applied Electrophysics Laboratories. He is now Patricia W. and C. Sheldon Roberts '48 Professor of Solid State Electronics, Professor of ECSE, Professor of Physics, Applied Physics and Astronomy, Director of Center for Broadband Data Transport Science and Technology, and co-Director of the NSF I/UCR Center “Connection One.” In 2001-2002, he served as Acting Director of Center for Integrated Electronics at RPI. Dr. Shur is Fellow of IEEE, Fellow and life member of the American Physical Society, Fellow of Electrochemical Society, Fellow of World Innovation Foundation, AAAS, Life Member of IEEE MTT, of Sigma Xi, and of Humboldt Society of America, member of Eta Kappa Nu, and Tau Beta Pi, Electromagnetic Academy, Materials Research Society, ASEE, Sigma Xi, elected member and former Chair of US Commission D, International Union of Radio Science (URSI), and elected member of NRC of URSI (2003-2004). Dr. Shur is Editor-in-Chief of the International Journal of High Speed Electronics and Systems and of the book series on Selected Topics in Electronics and Systems (World Scientific), Regional Editor of physica status solidi, Member of the Honorary Board of Solid State Electronics, member of the International Advisory Committee of Journal of Semiconductor Technology and Science, Vice-President for publications of the IEEE Sensor Council, and member (1999-2003) and Chair (2004-2005) of the IEEE Prize Papers/Scholarships Award Committee. He is also Distinguished Microwave Lecturer of IEEE MTT and Distinguished Lecturer of IEEE EDS. In 1990-1993, he served as an Associate Editor of IEEE ED Transactions.

Dr. Shur has also served as Chair, Program Chair, Organizing and Program Committee Member of many IEEE conferences. He is one of co-developers of AIM-Spice (with over 60,000 users world wide) and co-founder of Sensor Electronics Technology, Inc. In 1994, the Saint Petersburg State Technical University awarded him an Honorary Doctorate. He has published many technical papers, authored, co-authored or edited 33 books and 28 book chapters, and has been awarded over 30 patents on semiconductor devices and circuits. Several of his technical publications received the best paper awards. Among his other awards are the Gold Medal of the Russian Ministry of Education, several A. F. Ioffe Best Paper Awards, van der Ziel Award, Senior Humboldt Research Prize, Pioneer Award from Compound Semi, RPI School of Engineering Research Award, and Commendation for Excellence in Technical Communications. Dr. Shur is listed by the Institute of Scientific Information (ISI) as a highly cited researcher in engineering.

For Further Information: contact Richard Snyder (973) 492-1207, Edip Niver (973) 596-3542, Har Dayal (973) 633-4618, or Kirit Dixit (201) 669-7599.