Kamau Prince

LayTec AG
  • Advanced semiconductor metrology and process control using UV-A/UV-B LEDs

    Kolja Haberland, LayTec AG
    Kamau Prince, LayTec AG
    Volker Blank, LayTec AG
    Johannes Zettler, LayTec AG

    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 reflect-ometry 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.

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