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Different homo epitaxial 4H-SiC commercial wafers were undergone hydrogen etching process that was developed in the reaction chamber of a Hot Wall Chemical Vapor Deposition (HWCVD) reactor. We have studied the effects of physical desorption to point out the morphology and the structural changes of epitaxial surfaces.An optical microscopy inspection was made to trace out a map of defect areas before and after etching treatments. We have analysed the morphological evolution of the surface in every etching process step by means of marked area on the defect map. We also achieved some other important information, concerning structural and morphological changing, by performing Atomic Force Microscopy and Micro Raman spectroscopy analysis on the same defect marked area.The etched epilayers showed a significant reduction of defects density and a good surface morphology. On investigated samples we fabricated Schottky diodes, their electrical behaviour compared to the devices fabricated on not etched epitaxial layer highlights the surface quality improvement and the increasing of SBD working yield. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Silicon carbide (SiC) is a wide band gap semiconductor, interesting for its physical properties such as high breakdown field, high saturated drift velocity and high thermal conductivity, which has been intensively studied in the last years. Although the high potentiality of this material, the SiC technology shows at the moment some limitations, indeed, the reliability of SiC-based devices is strictly correlated to the defects present in the crystalline structure. 4H-SiC epilayers were grown by Hot Wall Chemical Vapor Deposition (at 1600 °C) and by Sublimation techniques (at 2000 °C). A surface investigation of the epilayers has been performed finding particular physical finger-prints correlated with several kind of defects aimed at giving an important feedback to the epitaxial growth processes. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)