Semiconductor Devices for Pulsed Power and High Voltage Applications
One of the limiting components of high current, high voltage systems is the switch. The switch is required to block high voltage, conduct high current, operate at high frequency and survive under extreme conditions such as high dv/dt, di/dt and high action. Applications such as High Power Microwaves, High Energy Lasers, EM guns, EM armor, Biological and Environmental, accelerators and radars are just some of the systems that require high voltage and high current switches. The two main areas of switching are continuous applications such as in high voltage power supplies, and power conditioning in power electronics applications. The next application for power switches are in the area of pulsed switching where the frequency of operation may be lower, but the peak current and voltage can be significantly higher. Semiconductor power switches have matured over the years and are being integrated into pulsed power systems. Bipolar type switches such as thyristors and GTOs are ideal for high current pulsed applications. Unipolar devices such as MOSFETS and JFETS are ideal for continuous operation. The most popular device for continuous operation is the IGBT. The IGBT is a bipolar device that can handle high current and block high voltage, but the switching frequency is much lower than the MOSFETs. In order to reach the high voltage and current requirement for pulsed power applications, individual devices are stacked in series and parallel. This leads to other challenges such as packing, thermal management and gate driver design.
Silicon (Si) power semiconductors were the devices of choice for pulsed power and continuous power applications. The Si material is reaching its limit for high voltage, high current and high temperature operation. New wide bandgap materials such as Silicon Carbide (SiC) and Gallium Nitride (GaN) are being investigated for high pulsed power and continuous applications. SiC is more mature that GaN and some low power devices are being introduced to the market place. Research of SiC devices have demonstrated very high voltage and temperature operation.
This presentation will focus on power semiconductors for pulsed and continuous operations. An overview of semiconductor physics will be given with a focus on the basic parameters such as bandgap, avalanche, mobility, and lifetime. A review of the operation of power devices such as IGBTs, Thyristors, GTOs, and Power diodes such as P-I-N and JBS will be given. Thermal and electrical performance will be covered in addition to failure analysis and limitations of the devices. A discussion of SiC power devices, results, and updates on the state-of-the-art of the devices will be covered. Modules for high voltage and high current applications will be discussed, along with how to select the appropriate devices for the right applications. Silvaco simulation results will be provided to determine the high electric field across the devices under high blocking voltage. Simulation results will also be provided to show the high current density and high temperature areas within the devices.
Dr. Stephen B. Bayne received his PhD, MS and BS degrees in Electrical Engineering from Texas Tech University. After completing his Doctorial studies, he joined the Naval Research Lab (NRL) where he was an Electronics Engineer designing advanced power electronics systems for space power applications. After two and a half years at NRL, Dr. Bayne transferred to the Army Research Lab (ARL) where he was instrumental in developing a high temperature power electronic program. Dr. Bayne was promoted to Team Lead at ARL where he led the power components team which consisted of five Engineers. As the Team Leader, Dr. Bayne was responsible for advanced research in high temperature and advance power devices for Army applications. In addition, he developed internal research and also generated Small Business Initiative Research (SBIR) topics and worked as the Contracting Officer Representative (COR) on several contracts. After one and a half years as Team Lead, Dr. Bayne was promoted to Branch Chief of the Directed Energy Branch where he managed 16 Engineers, Technicians and support Staff. Dr. Bayne managed a multi-million dollar budget, and was responsible for recruiting, development, and performance evaluation of members in the branch. After eight years at the ARL, Dr. Bayne transitioned over to academia where he is currently a Professor at Texas Tech University (TTU). His research interests at Texas Tech are Power Electronics, Pulse Power, Power Semiconductor Devices and Renewable Energy. Dr. Bayne has over 148 publications and has given three short courses in the area of power semiconductors for pulsed applications. He also co-authored a chapter in the book Advances in Silicon Carbide Processing and Applications. Dr. Bayne has given several invited talks and developed the Power Semiconductors course at TTU. In addition, he has a very strong research program at TTU in the area of power semiconductors for high energy applications and has attracted over $7,723,000 in the last eight years.
Dr. Bayne has won several awards at ARL including the Army Research Lab Achievement Award for Human Resources Development, the Army Research Lab Achievement Award for Engineering, the Army Greatest Invention Award and the Army Research and Development Award. He also received the TTU Lockheed Martin Excellence in Engineering Teaching award, and the IEEE Texas Tech University Student Branch Teacher of the Year award. He was inducted into the TTU Teaching Academy in 2013. Dr. Bayne is also a veteran of the military, where he served four years in the Air Force.