Integrated Active Matrix Technologies for MicroLED displays
Ioannis (John) Kymissis, Kenneth Brayer Professor of Electrical Engineering at Columbia University and Chair of the Department of Electrical Engineering
Presentation Abstract
MicroLEDs offer extraordinary performance characteristics and potential in both display and non-display applications. The long lifetime, high achievable luminance, outstanding color points, and high efficiency achievable using microLEDs is well recognized and has led to a number of demonstrations including application in microdisplays, intermediate-format transparent displays, large format chiplet-based mass transfer displays, and non-display applications such as superresolution microscopy.
There are, however, a number of challenges which remain in the microLED space. The first is the need for an active matrix to drive displays of any useful size. A second is the need for electrical and optical isolation of smaller pixels. A third is the need for high throughput approaches to examine and improve yield in devices. In this presentation we will discuss some of the solutions demonstrated at Lumiode and Columbia University to approach these issues. Lumiode has demonstrated the direct integration of a high performance backplane directly on the LED substrate using thin film transistors to provide the addressing, switching, and drive for displays. Lumiode has further demonstrated the use of ion implantation to deactivate the dopants in LED contact layers, permitting additional device isolation (down to 1.5 micron pixel size) without the introduction of etched areas that drive recombination and reduce efficiency. We will also review the use of cathodoluminescence for device analysis, strategies for contact optimization, and the development of smart chiplets, which permit the simultaneous assembly of an LED array and transistor backplane. The combination of these approaches offers a number of new elements potentially across a range of microLED display formats.
Ioannis (John) Kymissis
Ioannis (John) Kymissis is the Kenneth Brayer Professor of Electrical Engineering at Columbia University and Chair of the Department of Electrical Engineering. He graduated with his SB, M.Eng., and Ph.D. degrees from MIT. His M.Eng. thesis was performed as a co-op at the IBM T.J. Watson Research Lab on organic thin-film transistors, and his Ph.D. was obtained in the Microsystems Technology Lab at MIT, working on field-emission displays. After graduation, he spent three years as a postdoc in MIT’s Laboratory for Organic Optics and Electronics, working on a variety of organic electronic devices, and also as a consulting engineer for QD Vision (later acquired by Samsung Electronics). He joined the faculty at Columbia University in electrical engineering in 2006. He is a fellow of the IEEE and SID, and was the general chair for the 2014 Device Research Conference.