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Normal incidence reflectivity measurements were carried out in an AIX 2000G3HT Multiwafer Planetary ReactorR MOVPE system, a large scale production tool for GaN-based devices, and in the single wafer AIX 200 RF system. In situ monitoring was used to investigate nucleation behavior, temperature dependence of GaN growth, and the deposition of GaN/InGaN multiquantum wells, especially the quality of interfaces. The obtained results were compared with RT photoluminescence, and high resolution X-ray measurements. The optimized SQW and MQW structures were embedded in Si and Mg doped cladding layers. Contacting the layers with simple metal electrodes without any contact processing results in an intense green electroluminescence. Electroluminescence test structures emitting at 540 nm show minimum forward voltages around 4V with a current of 20 mA. Since no contact technology is applied this is a proof of high p-type doping and excellent structural properties of the InGaN. We found a standard deviation of the wavelength at about 533 nm of less than 1% across the wafer. Since these results were reproducibly obtained for structures emitting in the blue or green the basic demands of a reliable production equipment are fulfilled: (1) high precursor yield (typical 20% for the Ga source) (2) uniformity of electrical and optical performance (3) demonstration of electroluminescence with high efficiency.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only. |
