Application of 280nm In-Situ Metrology to study the Influence of AlN Templates on Surface Roughness and Strain Effects in UVA/UVB LEDs

K. Prince1, A. Knauer2, A. Mogilatenko2, M. Weyers2, and K. Haberland1

Published in:

Int. Conf. on Compound Semiconductor Manufacturing Technology (CS ManTech 2020), Dig., pp. 33-36 (2020).

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Abstract:

Traditional in-situ reflectometry sensing at blue (405 nm), red (630 nm) and NIR (950 nm) wavelengths cannot resolve variations in InAlGaN surface roughness or layer thickness with the precision necessary for effective in situ process control. LayTec has developed in situ reflectance metrology at 280 nm to address this need.
We report successful application of in situ UV reflectometry and curvature, distinguishing between various phases of strain relaxation and surface relaxation during non-pseudomorphic growth of Al0.5Ga0.5N on AlN/sapphire. Results were validated by XRD, TEM and AFM. Results illuminate the influence of reduced TDD on relaxation effects during growth of UVA and UVB LED structures.

1 LayTec AG, Berlin, Germany
2 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Berlin, Germany

Keywords:

UV LED, in-situ metrology, MOVPE, EpiCurveTT.