There is a growing interest in micro LED as the novel ingredients of bright and power-efficient displays. The focus seems more on the transfer technology than LED itself, because they believe that making LED smaller than before will do. However, unlike when it is used as a back-light source, LED should play a pivotal role in the micro LED display, and its design should be changed to comply with the new requirements such as extremely high yield to minimize the replacement of “dead” pixel, characteristics uniformity not only in the wafer but also between wafers for color consistency over millions of chips, and transfer-compatible chip structure.
The talk will briefly introduce the evolution of LED application to display, then review the device structure of typical blue and green GaN LED with an emphasis on the material aspects. With the basis of device physics, we will discuss the size effect of micro LED such as increased surface-to-volume ratio and the fluctuation of defect density. The talk will also cover various mass-transfer methods and high-speed PL inspection method, both of which were newly introduced for micro-LED application. There will be a brief touch of the red InGaAlP LED, the other component for full-color display.
Dr. In Kim acquired BS (’89), MS (’91), and Ph.D (’96) degrees in Physics all from Seoul National University, and then he worked as a postdoc in the Electrical Engineering Department of University of Southern California. Throughout his Ph.D and postdoc, he studied the MOCVD growth of various compound semiconductors such as InAlGaAs, InGaAsP, and InGaN, and their application to photonic devices such as lasers, amplifiers, and resonant cavity couplers. He joined Samsung Electronics in 1999, as a starting member of Opto-electronics Business Division for telecommunication component production, where he developed the amplifier- and modulator-integrated laser for the first time. He moved to Digital Media Communication R&D Center in 2003 to develop laser diodes for FTTH and optical interconnection applications.
In 2009, he joined the manufacturing team of Samsung LED, where he had been leading the MOCVD production line until 2015. His MOCVD line managed to equalize the device performance from more-than-100 MOCVD reactors by high-level tool-to-tool matching. It was a unique approach never tried in the LED industry and was only possible by deep understanding of MOCVD process and LED device physics. Then he moved to the LED development team and worked in the GaN-on-Si growth project. Since July 2017, he is the Chip Team Director of OE Solutions in Gwangju, the leading telecommunication components manufacturer in Korea. Now, he is leading the development of 25Gb/s lasers for 5G wireless network application.