News Article
Laytec installs First Single-Port EpiCurveTT for Aixtron Showerhead
The firm has installed the system at the Fraunhofer Institute, Germany. It will be used for growth control of GaN on Silicon substrates.
LayTec has successfully installed an EpiCurveTT on an Aixtron Close Coupled Showerhead (CCS) MOCVD system at Fraunhofer Institute for Applied Solid State Physics (IAF) in Freiburg, Germany.
This is the first time an EpiCurveTT has been installed on a showerhead system on only one viewport.
In the past, since the viewports of such systems are so small, 2 separate windows were used: one for curvature and one for temperature and reflectance measurements. Now, due to the improved design, all three parameters are measured through one standard AIX CCS viewport.
Chunyu Wang and his team at IAF will use the tool for growth control of GaN on silicon substrates. The simultaneous in-situ monitoring of wafer temperature, reflectance and curvature will be used to engineer the stress in the epilayers.
Wang commented, “The new sensor will help us to get flat and crack-free GaN layers on Si substrates for future sophisticated electronic devices.”
Recently, LayTec launched EpiCurveTT AR (advanced resolution) for measurements of the aspherical curvature component during epitaxial growth. The tool is claimed to be the perfect solution for Planetary and other gas-foil rotation MOCVD systems where the azimuth of the rotating wafers is unknown.
The standard EpiCurveTT without AR measures randomly either along the major axis (larger bow - blue arrow in Fig. 2) or along the minor axis (smaller bow - red arrow in Fig. 2). In a Planetary reactor the phase of rotation is unknown. As a result, the signal looks “noisy” (red line in Fig. 3): it oscillates between the maximum and the minimum of the azimuthal aspherical bow.
The new AR tool measures curvature along two perpendicular axes and eliminates 2nd order azimuthal bowing effects. In Fig. 3, the black line shows the curvature signal of the new EpiCurveTT AR sensor. The signal-to-noise ratio of the tool with advanced resolution improves the curvature signal from ±8 km-1 (red line) to ± 0.2 km-1 (black line) and measures only the main curvature component by eliminating the aspherical contribution.
Even the quantity of asphericity can be extracted by analysis of the advanced resolution signal.
At the end of June LayTec and its distribution partner in Taiwan Challentech International Corp. welcomed more than 200 industrial customers at user seminars in Hsinchu and Tainan.
LayTec presented the latest developments: the Pyro 400, EpiCurveTT AR and AbsoluT. Bernd Schineller of Aixtron reported about benefits of LayTec sensors in Aixtron Planetary and Crius systems. The talks are now available for download on LayTec website.
