The consumption of and the need for energy around the globe is constantly and exponentially increasing. Especially electricity is one the most important resources for which the demand is rapidly increasing. The silicon used in power electronics technology is the leading material that dominates the microelectronic devices market. However, in today’s technology, we’re witnessing a switch from silicon to new technologies and materials that will increase the productivity of energy usage and prevent wasting electricity. One of these new materials is Gallium Nitrate (GaN).
GaN has a wide array of areas it can be used in, such as electric cars that need durable materials, automotive lighting equipment, satellites, high-speed trains, overhead power lines, radars used in the arms industry. It will, however, not only be used in many more areas in the near future such as energy, informatics, and space technologies but also be irreplaceable in staple industry fields.
One of the scientists conducting research in this field is Asst. Prof. Nazlı Dönmezer from Boğaziçi University Department of Mechanical Engineering. Dönmezer graduated with a BS and MS from METU (Middle East Technical University) Department of Mechanical Engineering. Having earned her Ph.D. from the Georgia Institute of Technology in Atlanta, Dönmezer started working in Boğaziçi University in July 2017.
Dönmezer and her team of researchers are working on GaN-based transistors (chips) to understand and document their thermal behavior using various measurements and models. They are working to better understand the problem of overheating when these chips are loaded with power, especially in settings requiring high power/frequency such as radars or electric cars.
Stating that the overheating parts are nanometrically small, which means that the current measuring technologies do not allow point-measurement of the temperature on such a small scale, Dönmezer expressed that they’re trying to answer the question “Can we model the temperature even when we can’t measure it?” In the project she’s conducting since December 2017 within the TÜBİTAK (The Scientific and Technological Research Council of Turkey) 1003 program (Primary Subjects R&D Funding Program), Dönmezer is studying the devices that cause temperature concentration in chips in order to see how the heat conduction works and to come up with solutions to the modeling and design processes of such devices so as to prevent overheating.
“Overheating is a major problem in these devices. This may lead to performance loss or may shorten their lifetime. When we measure or rather understand the temperature of these chips, we can find out for how long they can function before breaking down and help design better devices to prolong their lifetime.”
Dönmezer and her team are collaborating with ASELSAN (Military Electronic Industries) to achieve this. Aselsan-Bilkent MicroNano Technologies Inc. (AB MikroNano), founded by Aselsan and Bilkent University in 2014, has been producing Gallium Nitrate transistors and microchips for the first time in Turkey and Dönmezer has been conducting research on the devices produces by this company.
Dönmezer added: “Producing chips is not an easy process, you need a certain level of knowledge and investments. We’ve been very slow and lagged behind when it comes to silicon and missed that opportunity. However, we still have a chance to switch over to the Gallium Nitrate technology. Using the trial-and-error method while designing a device costs a substantial amount of money and time. To give you an example, people are using diamond substrates to produce these devices around the world as diamond’s heat conductivity is very high. However, diamonds are costly. We need to carefully determine and select where to use diamonds in order to get the best results. For this reason, we’re focusing not only on measuring but also electrical and thermal modeling. We’re doing these measurements in Boğaziçi University Advanced Technologies R&D Center where we find the high-tech devices that can perform surface analysis, microanalysis and detailed characterization.”