In-situ metrology system maker LayTec AG of Berlin, Germany says that Dr Tony SpringThorpe of the National Research Council of Canada recently reported fast and easy temperature calibration of all three heating zones of his showerhead metal-organic chemical vapour deposition (MOCVD) reactor by using LayTec's AbsoluT for calibration of EpiTriple TT, which monitors the growth of As- and P-based devices via three measurement heads at three different viewports.
Picture: AbsoluT attached to a showerhead reactor lid for calibration.
The precision of temperature measurements is crucial for proper in-situ monitoring of epitaxial growth, LayTec notes. It is even more important if you measure temperature at different points on the same wafer, on different wafers or in different reactors simultaneously or if you compare the temperature of different runs.
AbsoluT sets up one exact reference point for pyrometry measurements at three viewports, where temperature variations are often caused by adjustment, window coating or manufacturing tolerances of the equipment. "AbsoluT is a quantum leap compared to the former calibration methods," comments SpringThorpe. "It takes only 5 minutes to calibrate all three heads and requires no further calculation," he adds. "Hence, I can take under real-time control all three heating zones. This helps enormously to grow uniform buffer and MQW [multiple quantum well] structures."
