Zuechtung und Charakterisierung von SiC-Einkristallen und Epitaxieschichten Abschlussbericht

It was aim of the project, to catch up to the international state of the art concerning the SiC material development and thus to ensure the supply with device suited SiC substrates on a long term basis. By a joint effort of crystal growth experiments and numerical simulation of the sublimation growth technique it was possible to reduce the defect density in the grown crystals significantly (micropipe density 70-400 cm"-"2 depending on wafer diameter, dislocation density 5000 cm"-"2-2000 cm"-"2, doping range n=1-5 10"1"8 cm"-"3). The diameter of the crystals was enlarged from 25 to 35 mm. The above mentioned data already partly meet the properties of commercially available substrates of US manufacturers. SiC epitaxy - an important link between substrate and device technology - served as a sensible characterization method for the quality of SiC substrates produced either externally or within this project. It appears that not only the crystal quality but also the surface properties of the SiC substrates have important influence on the characteristics of the epitaxial layers. For the epitaxial process itself significant improvements could be achieved as well (background impurity concentration <10"1"4 cm"-"3, thickness inhomogeneity <5%). First demonstrator devices (Schottky diodes) were built on substrates manufactured within this project, and, thereby, the suitability of these substrates for device technology was tested. The SiC bulk crystals and epitaxial layers grown during the project were analyzed with optical and electrical characterization tools (partly new developed). The results served for optimization of the respective manufacturing technique. For SiC power electronics applications, both large defect free areas and an as high as possible substrate conductivity are necessary. Therefore further research efforts are mandatory. In order to reduce the manufacturing costs of SiC devices, it is furthermore very important to increase the crystal diameter to two inches. (orig.)SIGLEAvailable from TIB Hannover: F97B2254+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman