High-Temperature Nucleation of Cubic Silicon Carbide on (0001) Hexagonal-SiC Nominal Surfaces

Abstract

International audienceThe development of 3C-SiC crystals from <0001> oriented hexagonal seed has always suffered from systematic twinning that appears during the nucleation step of the layer. To investigate the possibility to reduce or eliminate the incoherent twin boundaries at high temp. (for conditions close to bulk growth ones), we conducted an exptl. study on 3C-SiC nucleation. A mechanism for the selection of one 3C-SiC orientation among the two possible is proposed. It is based on a strong interaction between the a-SiC substrate steps and the anisotropic lateral expansion of the b-SiC domains. This model is confirmed by cross-sectional high resoln. transmission microscopy observations of the a-b interface. The mechanism is discussed with respect to the surface polarity (Si or C faces), the miscut angle, and the substrate polytype

Role of surface effects on silicon carbide polytype stability

“…[16] and references therein). The few studies dealing with the effect of polarity on nucleation and growth of 3C-SiC report a higher nucleation density on C face [17,18]. Our calculations are in disagreement with these experimental facts but could be explained by a lower surface energy of the C face.…”

Study of the 3C-SiC nucleation from a liquid phase on a C face 6H-SiC substrate

“…As a matter of fact, growing 3C polytype on a-SiC substrate generates a high density of crystalline defects related to the systematic formation of twin boundaries (also called double positioning boundary or DPB). The few works dealing with the elimination of twin boundaries (or at least a significant reduction of their density) concern almost exclusively the Si face of a-SiC substrates [5][6][7][8]. To the best of our knowledge, only few studies deal with the reduction of the twin density inside the 3C layers grown on the C face.…”

“…The most relevant one is probably Ref. [8] in which authors studied the 3C nucleation stage in a specially designed sublimation furnace. But the conclusion was quite pessimistic on the possibility of twin boundary elimination on the C face.…”

3C-SiC Heteroepitaxy on Hexagonal SiC Substrates

“…The nucleation of 3C on on-axis hexagonal polytype has also been addressed at high temperature and key points to get single domain were related to the initial step density of the substrate and the interaction between the steps and the anisotropic lateral growth of the 3C domains [13]. With top-seeded solution method, DPB free 3C layers were obtained using off-axis 6H-SiC substrates, but towards [1-100] instead the standard [11][12][13][14][15][16][17][18][19][20] [14]. Molecular beam epitaxy using solid source evaporation is proposed to achieve the growth of heteropolytypic structures, however many challenges are still not resolved with this technique [15].…”