Hexagonality and Stacking Sequence Dependence of Etching Properties in Cl₂-O₂-SiC System

Abstract

Thermal etching of hexagonal (4H-, 6H-, 8H- and 10H-), rhombohedral (15R- and 21R-), and cubic (3C-) SiC Si-faces was performed between 900 and 1000oC in a mixed gas of chlorine (Cl2) and oxygen (O2). In the case of well oriented Si-faces, the 3C-SiC (111) substrate was etched fastest in polytypes. The etching rate in the dislocation-free area depended on the hexagonality. Etch pits with definite shapes appeared, which depend on the type of dislocation and crystal structures. On the basis of these results, etching properties are discussed.

Comparative study on dry etching of α- and β-SiC nano-pillars

“…The observed trend is comparable to the results reported elsewhere [19], which shows the etch-pit depth of 3C-SiC higher than that of other polytypes. In another study, the depth of etch pit decreased with increasing the hexagonality of SiC [19]. But, there is no obvious difference in etch rates of SiC pillars according to hexagonal polytypes and crystallographic orientations.…”

“…It is thought that low crystalline quality of heteroepitaxially grown 3C-SiC layer, which is induced by the large lattice mismatch (almost 20%) between the 3C-SiC layer and the Si substrate, could be one of the possible reasons of higher etch rates than in the case of the single crystal substrates of α-SiC [18]. The observed trend is comparable to the results reported elsewhere [19], which shows the etch-pit depth of 3C-SiC higher than that of other polytypes. In another study, the depth of etch pit decreased with increasing the hexagonality of SiC [19].…”

“…The α-SiC substrates used in this study were product grades of Tankeblue 4H and 6H-SiC (0001) on-axis substrates [9]. The 6H-SiC (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) substrates were grown by the conventional physical vapor transport method, which has been presented elsewhere [10]. For β-SiC (001) substrate, the 3C-SiC layers were heteroepitaxially grown on Si (001) substrates [11].…”

“…If a top-down approach is applied into these different polytypes of SiC layer, the SiC nanostructures may easily be achieved with different physical properties, which can lead to further exploit the applications of SiC nanostructures. In this letter, the etching behavior of SiC nanopillars depending on the different polytypes and crystallographic orientations: 4H-SiC (0001), 6H-SiC (0001), 6H-SiC (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) and 3C-SiC (001), is presented.…”

Photoluminescence of 8H-SiC

“…Beside the experimental work described here, micro-Raman spectroscopy and thermal oxidation were used to determine the polytype and the polarity of the substrates [6]. The substrates were polished to obtain an off angle of ~ 5º toward the [11-20] direction.…”