Active‐Matrix GaN µ‐LED Display Using Oxide Thin‐Film Transistor Backplane and Flip Chip LED Bonding

A 2 in. active‐matrix light‐emitting diode (AMLED) display by integration of the micro‐LED onto the oxide thin‐film transistor (TFT) backplane using flip chip bonding is reported. A blue‐emitting micro‐LED (µ‐LED) with a size of 90 × 50 µm2 is fabricated on the GaN epi grown on a sapphire substrate....

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Bibliographic Details
Published in:Advanced electronic materials 2019-03, Vol.5 (3), p.n/a
Main Authors: Um, Jae Gwang, Jeong, Duk Young, Jung, Younghun, Moon, Joon Kwon, Jung, Yeon Hong, Kim, Seonock, Kim, Sung Hwan, Lee, Jeong Soo, Jang, Jin
Format: Article
Language:English
Subjects:
a‐IGZO
flip chips
GaN LEDs
laser‐lift off (LLO)
oxide thin film transistors (oxide TFTs)
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Summary:A 2 in. active‐matrix light‐emitting diode (AMLED) display by integration of the micro‐LED onto the oxide thin‐film transistor (TFT) backplane using flip chip bonding is reported. A blue‐emitting micro‐LED (µ‐LED) with a size of 90 × 50 µm2 is fabricated on the GaN epi grown on a sapphire substrate. The amorphous indium‐gallium‐zinc‐oxide (a‐IGZO) TFT on glass exhibiting the mobility of 18.4 cm2 V−1 s−1, turn‐on voltage (V ON) of 0.2 V, and subthreshold swing 0.25 V dec−1, is used for LED backplane. A two TFT and one capacitance pixel structure is utilized for driving 128 × 384 AMLED with 120 Hz frame rate. The laser lift‐off process with flip‐chip bond allows the transfer of the µ‐LED chips with 49 152 pixels onto the TFT backplane, demonstrating a 2 in. AMLED display with a good gray scale image. The current efficiency of µ‐LED is found to be 12.9 Cd A−1 at the luminance of 630 Cd m−2. Therefore, a‐IGZO TFT backplane can be used for µ‐LED displays. Fabrication of active‐matrix micro‐light‐emitting diode (LED) display using oxide thin‐film transistor (TFT) backplane is reported. For both of the GaN micro‐LED on sapphire substrate and oxide TFT on glass substrate, integrated by the flip chip bond with LLO process is demonstrated. The high performance with the excellent stability of oxide TFT satisfies the active‐matrix light‐emitting diode display consisting of 128 × 384 matrix under the 120 Hz frame rate.
ISSN:2199-160X
2199-160X
DOI:10.1002/aelm.201800617