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22 May 2008


LayTec wafer curvature sensors sold for European R&D

LayTec says that its EpiCurve TT wafer curvature sensor (which is already its best selling product among GaN LED makers) is gaining recognition at European research institutions, with three systems having recently been sold for MOCVD systems in Europe. One has already been installed at CNRS-CRHEA (Centre de Recherche sur l'Hétéro-Epitaxie et ses Applications) in Valbonne, France.

Philippe de Mierry and co-workers are using the sensor on a home-built MOCVD system for monitoring GaN and InGaN LED growth on sapphire substrates. de Mierry’s team studies the effects of different backside polishing and coating, thicknesses, initial bowing and residual stress. Also, with the next generation of large 4” sapphire substrates, the homogeneity of the In content in the active layer of LEDs is becoming an issue. This requires good control of the surface temperature and wafer curvature during InGaN deposition, de Mierry says. “EpiCurve TT will help us to understand the role of these various substrate parameters on the evolution of the wafer curvature, and then to optimize the LED homogeneity,” says de Mierry.

A further EpiCurveTT has been sold to the University of Magdeburg in Germany. The team of professor Alois Krost will use it for GaN/Si growth control and, in particular, for in-situ monitoring of GaN-based Bragg mirrors and vertical-cavity surface-emitting laser (VCSEL) structures.

Finally, Germany’s Technical University of Berlin has purchased a Curve module as an upgrade for its spectroscopic reflectance sensor EpiR. Professor Michael Kneissl’s team is applying the sensor on a Thomas Swan Close Coupled Showerhead reactor for the optimization of InGaN laser and deep-UV LED growth. The EpiCurve TT system allows the combination of full spectroscopic reflectance control with wafer curvature, temperature and growth rate measurements, all in real time, LayTec says.

See related item:

LayTec introduces In-situ Monitoring Award

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