Plenary Lecture

Electronic Circuits for Switching-Time Reduction of Bipolar Semiconductor Devices

Professor Noel Y. A. Shammas
Faculty of Computing, Engineering and Advanced Technology
Staffordshire University
UK
E-mail: N.Y.A.Shammas@staffs.ac.uk

Abstract: Bipolar semiconductor devices are often used as switches in very high power electronic circuits and systems. They have replaced the old conventional gas filled tubes and vacuum devices in many applications. This is mainly due to the fact that solid-state devices are more efficient, smaller in size, cheaper and more reliable. In addition, solid-state devices are considered environmental friendly, since they do not contain nasty gases and toxic materials used in old devices.
The power level requirements and switching frequency are continually increasing in the power electronic industry, and this demands larger and faster switching devices. As a result, both bipolar and unipolar semiconductor devices have undergone continued improvement in current and voltage ratings, and switching speed. The main advantage of bipolar devices is their low conduction losses but their main disadvantage is the high switching losses which is due to minority carrier injection.
The Insulated Gate Bipolar Transistor (IGBT) combines the advantages of both. It has a simple gate drive circuit like that of the MOSFET, with high current and low saturation voltage capability of bipolar transistor. The main problem remains with the relatively long tail turn-off current. To reduce the turn-off time of the IGBT and other bipolar devices, different lifetime control techniques and structural changes have been developed and used. Details of these and new techniques developed by using auxiliary electronic circuits for reducing the turn-off time and increasing the switching speed of bipolar semiconductor devices will be presented.

Brief Biography of the Speaker:
Noel Shammas is currently a Professor in Microelectronics and Solid-State Power Semiconductor Devices in the faculty of Computing, Engineering and Advanced Technology, Staffordshire University. He received the M.Sc and Ph.D degrees from Salford University in 1972 and 1975 respectively. Since then he lectured and researched at different universities and industry.
Research work is primarily focused on Power Semiconductor Devices which includes mainly Power diodes, Light Emitting Diodes (LED’s), Insulated Gate Bipolar Transistors and Thyristors. Other related areas of research work includes Power Module Packaging technologies ( Both Conventional Press- pack and Smart pack designs) and Series/Parallel operation of high power semiconductor devices and their interaction with external circuits.
Professor Shammas has extensive experience in both experimental and theoretical research work and is recognised internationally for his significant contribution to research in the field of Power Semiconductor Devices. He has published over 120 journal and conference research papers as well as several invited Keynote Lectures, and has held several research grants from funding councils, Advantage West Midland (AWM), as well as from industry. He is a regular reviewer for many journals (including IEE Proceeding Electronic devices and systems, IEEE Transactions on power electronics, and Microelectronic Reliability) and international conferences (including the European Power Electronic conference - EPE, Microelectronic conference - MIEL, Universities Power Engineering Conference-UPEC, International Symposium Power Semiconductors-ISPS, etc…). He is a member of scientific committee for many international conferences (including MIEL, EPE, WCE, WSEAS, and Microtherm) and a steering committee member for EPE, UPEC, and ISPS international conferences. He is also a book reviewer for Prentice Hall International and McGraw Hill.