Stoichiometric and non-stoichiometric (10(1)over-bar0) and (11(2)over-bar0) surfaces in 2H-SiC: a theoretical study

We examine the atomic geometries, energetics and electrical properties of a variety of reconstructions at (10 (1) over bar 0) and (11 (2) over bar 0) surfaces in 2H-SiC using the density functional theory. in agreement with previous studies we find the stoichiometric surfaces to be semiconducting. However, the non-stoichiometric Si and C terminated reconstructions are found to be stable over a wide range of growth conditions. Some of these low energy surfaces show metallic-like character. They might, therefore, negatively influence the electrical properties of the material, if they occur as internal surfaces in extended defects, e.g. as micropipes or dislocations. (C) 1999 Elsevier Science Ltd. All rights reserved.