Impact of surface step heights of 6H–SiC (0001) vicinal substrates in heteroepitaxial growth of 2H–AlN

Enhancement of initial layer‐by‐layer growth and reduction of threading dislocation density by optimized Ga pre‐irradiation in molecular‐beam epitaxy of 2H‐AlN on 6H‐SiC(0001)

“…High-temperature-gas etching enables the step height of the 6H-SiC (0001) substrate to be controlled to 3 bilayers at large area (2 inch) and with high uniformity [7]. We exhibited that good-quality AlN was grown on 6H-SiC (0001) with 3-bilayer-height steps [8].…”

“…The smaller densities of spiral hillocks (seen as white spots in the images) were observed on the AlN layers with the longer Ga pre-irradiation times. The spiral hillock densities for Ga pre-irradiation times of 0, 3, and 5 seconds were 3×10 9 , 7×10 8 , and 4×10 8 , respectively. Especially, the spiral hillock of AlN layers pre-irradiated for 7 to 20 seconds were extremely small and the density were ~10 6 cm -2 .…”

“…The SiC substrates were treated by chemical mechanical polishing (CMP) followed by high-temperature H 2 gas etching to control the step height of the SiC substrates to be 3 bilayers [8]. After ex-situ and in-situ Ga cleaning [7], the SiC surface was exposed to a Ga beam (7×10 14 s -1 cm -2 ) for 0 to 30 seconds at the growth temperature of 600 °C .…”

Step bunching of vicinal6H-SiC{0001}surfaces

“…1,2 SiC is also an attractive candidate as a substrate for the heteroepitaxial growth of other materials. 3,4 A particularly exciting example ͑which motivated the present study͒ is the growth of epitaxial graphene by thermal decomposition of the basal surfaces of single-crystal 4H and 6H SiCs. 5 Nevertheless, SiC will not reach its anticipated potential until a variety of problems are solved, not least being the need to controllably grow device-quality single-crystal material on a large scale.…”

Extended study of the atomic step-terrace structure on hexagonal SiC (0001) by chemical-mechanical planarization

“…Based on the theory of crystallography and the research development of the hexagonal super-hard materials, such as gallium nitride (GaN), sapphire, 4H-and 6H-SiC [13][14][15][16][17][18], we know that all these materials have an obvious characteristics: if the (0 0 0 1) surface of wafer is approximately 0 • -off, the surface could emerge with atomic step-terrace structure after planarization [3,[19][20][21]. Strictly, for such hexagonal super-hard materials, besides the method of measuring the surface roughness parameter (Ra) of the wafer after planarization by surface measuring instrument, the formation surface atomic step-terrace structure is more persuasive and credible to verify the efficiency of the planarization technique, because the surface atomic step-terrace structure directly show the crystalline form of the surface.…”