MOVPE growth for UV-LEDs

A. Knauer^a, F. Brunner^a, T. Kolbe^b, V. Küller^a, H. Rodriguez^a, S. Einfeldt^a, M. Weyers^a, M. Kneissl^a,b

^a Ferdinand-Braun-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Strasse 4, 12489 Berlin, Germany
^b TU Berlin, Inst. for Solid State Physics, Hardenbergstr. 36, 10623 Berlin, Germany

Published in:
Proc. SPIE, vol. 7231, no. 72310G (2009).
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Abstract:
Challenges for the MOVPE growth of LED heterostructures for emission in the UV-A and UV-B spectral range are discussed. Special attention is given to the effects of strain in the In(Al)GaN active region as well as in the complete layer stack. Here in-situ monitoring of wafer bowing is shown to be an important tool for optimization of the growth sequence. We will compare different buffer layer technologies, in particular GaN/sapphire for LEDs emitting at 380 nm and AlN/AlGaN buffer for shorter wavelength LEDs. By increasing the aluminum content in the InAlGaN multiplequantum- well active region and by optimizing the composition and doping profile of the electron blocking layers UV LEDs with emission wavelength between 380 nm and 318 nm are demonstrated.

Keywords:
UV, ultraviolet, light emitting diodes, LEDs, AlN, AlGaN, AlGaInN, MOVPE, epitaxy.

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