From left, Professor Shin Byung-ha from the Department of Materials Science and Engineering, doctoral student Kim Chae-yeon, and Dr. Oki Gunawan from IBM T. J. Watson Research Center. (Photo provided by KAIST)
Korean researchers have developed a new analytical method that can detect ‘defects (electron traps)’ that interfere with electrical flow in semiconductors with approximately 1,000 times greater sensitivity than existing methods.
Korea Advanced Institute of Science and Technology (KAIST) announced on Jan. 8 that a joint research team led by Professor Shin Byung-ha from the Department of Materials Science and Engineering and Dr. Oki Gunawan from IBM T. J. Watson Research Center has developed a new measurement technique capable of simultaneously analyzing electron traps and electron transport characteristics.
Electron traps capture electrons, causing current leakage and degrading performance. To accurately evaluate semiconductor performance, it is necessary to determine how many electron traps exist and how strongly they capture electrons.
The research team focused on Hall measurement, which has been used for semiconductor analysis. Hall measurement is a method that analyzes electron movement using electric and magnetic fields. By adding light irradiation and temperature variation to this measurement approach, they obtained information that was difficult to confirm with existing methods.
When light is weakly irradiated, newly generated electrons are first captured by electron traps. Conversely, when light intensity is gradually increased, traps become filled, and subsequently generated electrons move freely. The research team was able to precisely calculate the amount and characteristics of electron traps by analyzing this transformation process.
The greatest advantage of this method is that multiple pieces of information can be obtained simultaneously with a single measurement. It can determine not only how fast electrons move, how long they survive, and how far they travel, but also the characteristics of traps that interfere with electron movement.
The research team first applied this technique to silicon semiconductors to verify its accuracy, then applied it to perovskites, which are attracting attention as next-generation solar cell materials. As a result, they precisely detected even very small amounts of electron traps that were difficult to detect with existing methods. They secured measurement capability approximately 1,000 times more sensitive than existing technology.
Professor Shin Byung-ha said, “We presented a new method that can simultaneously analyze electrical flow and interfering factors in semiconductors with a single measurement,” adding, “This will become an important tool for improving the performance and reliability of various semiconductor devices such as memory semiconductors and solar cells.”
The research results, with Kim Chae-yeon, a doctoral student in the Department of Materials Science and Engineering, participating as the first author, were published in Science Advances on January 1.
