Influence of stress and defects on the silicon-terminated SiC(001) surface structure

Abstract

Using ab initio calculations, we have investigated the influence of stress and defects on the reconstruction of the ͑001͒ Si-terminated surface of cubic SiC. We find that an unstrained bulk is terminated by a p(2ϫ1) reconstruction under tensile stress. This stress can be substantially relieved by the removal of dimers. Applying further tensile stress lowers the surface symmetry and leads to a c(4ϫ2) pattern. The structural properties of this reconstruction are in very good agreement with recent measurements, suggesting that stress in SiC samples is responsible for the c(4ϫ2) reconstruction observed experimentally. Furthermore, we have analyzed temperature and charging effects on the surface properties and made a comparative study of theoretical and experimental STM images.

Hydrogen-induced3×1phase of the Si-rich3C−SiC(001)surface

“…On the Si-terminated SiC͑001͒ surface, the importance of the surface stress has been indicated and the generation of missing dimer defects was shown to induce a phase transformation. 20 Theoretical considerations of the effect of missing dimer defects on the surface structure are promising in the understanding of the present discrepancy between the theoretical results and our photoemission studies. 17 *Author to whom correspondence should be addressed.…”

Multiconfigurational self-consistent field study of the silicon carbide (001) surface

“…The CASSCF͑4,4͒ calculation predicts a symmetric ͑unbuckled͒ Si-SiC ͑001͒ dimer structure similar to the periodic DFT calculations. 23,27 The highest occupied molecular orbital ͑HOMO͒ and the lowest unoccupied molecular orbital ͑LUMO͒ are ͓Fig. 2͑a͔͒ and * ͓Fig.…”

“…1͑b͔͒. Catellani et al 14,27 proposed, based on DFT calculations, that tensile stress induces the 4ϫ2 reconstructions consisting of alternating long ͑up͒ and short ͑down͒ dimers.…”

“…While the previous theoretical studies on SiC ͑001͒ surfaces were performed using empirical potentials, 15,16 semiempirical molecular orbital [17][18][19] calculations and DFT 14,[20][21][22][23][24][25][26][27][28][29][30][31][32] calculations, there have been virtually no ab initio calculations 33 performed on these systems. In particular, it may be important to employ multiconfigurational wave functions to describe the structures of SiC ͑001͒ surfaces by analogy with the dimer of the Si ͑001͒ surface, since the latter a͒ Electronic mail: tamura@cphys.s.kanazawa-u.ac.jp b͒ Electronic mail: mark@si.fi.ameslab.gov exhibits significant partial diradical character.…”

Trends in bonding configuration at SiC/III–V semiconductor interfaces

“…There has been increasing interest in silicon carbide (SiC) due to its favorable electronic properties, anomalous charge transfer, and extreme elastic and thermal properties [1][2][3][4][5] . The technological realization of self-aggregating wires 6,7 and quantized homostructures 8 make it one of the most promising materials for nanodevices, microelectronics, sensors, and highpower, high-temperature devices.…”