The wafer curvature sensor EpiCurve® TT, which is already LayTec‘s bestseller among GaN LED manufacturers worldwide, is gaining more and more recognition at European research institutions, as well. Recently, three EpiCurve® TT sensors were sold for MOCVD systems in Europe. One of them has already been successfully installed at CRHEA / CNRS in Valbonne, France.
Philippe de Mierry and co-workers use the sensor on a homebuilt MOCVD system for monitoring of GaN and InGaN LED growth on sapphire substrates. According to Mr. de Mierry, his team studies „effects of different backside polishing and coating, thicknesses, initial bowing and residual stress. Furthemore, with the next generation of large 4” sapphire substrates, the homogeneity of the In content in the active layer of LEDs becomes a real issue. This requires a good control of the surface temperature and wafer curvature during the In- GaN deposition. EpiCurve® TT will help to understand the role of these various substrate parameters on the evolution of the wafer curvature, and then to optimise the LED homogeneity.“
A further EpiCurve®TT has been sold to the University of Magdeburg in Germany. The team around Prof. Alois Krost will use it for GaN/Si growth control and especially for in-situ monitoring of GaN-based Bragg mirrors and VCSEL structures.
The Technical University of Berlin, Germany, has purchased a Curve® module as an up-grade for its spectroscopic reflectance sensor EpiR. Prof. Michael Kneissl and his team apply the sensor on a Thomas Swan Close Coupled Showerhead reactor for optimization of InGaN laser and deep-UV LED growth. The EpiCurve®R TT system allows combining full spectroscopic reflectance control with wafer curvature, temperature and growth rate measurements, all in real time.