Bow Reduction of AlInGaN-Based Deep UV LED Wafers Using Focused Laser Patterning
H.K. Cho1, A. Külberg1, N. Lobo Ploch1, J. Rass1, J. Ruschel1, T. Kolbe1, A. Knauer1, A. Braun1, O. Krüger1, S. Einfeldt1, M. Weyers1, and M. Kneissl1,2
Published in:
IEEE Photonics Technol. Lett., vol. 30, no. 20, pp. 1792-1794 (2018).
Abstract:
We investigated the effect of bow reduction of AlInGaN-based deep-ultraviolet light-emitting diode (DUV LED) wafers using internally focused laser patterning. The laser-induced stress inside of the sapphire substrate was found to increase with increasing density of laser lines and decreasing distance of the laser lines to the back surface of the sapphire substrate. By adjusting the laser process, the convex bow of DUV LED wafers could be almost completely eliminated. This bow reduction resulted in an improved uniformity of the LED forward voltage across the wafer compared to the reference wafer without laser patterning.
1 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, 12489 Berlin, Germany
2 Institute of Solid State Physics, Technische Universität Berlin, 10623 Berlin, Germany
Index Terms:
Deep UV, light emitting diodes (LEDs), AlGaN, wafer bow, laser patterning, LED performance.
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