Formation of periodic steps with a unit-cell height on 6H-SiC (0001) surface by HCl etching

Step bunching on 6H-SiC (0001)-vicinal face etched by HCl at 1390-1500 degrees C is investigated by atomic force microscopy. When the substrate has the inclination toward near [01 (1) over bar 0] or even [11 (2) over tilde 0], continuous parallel and periodic microsteps with six-bilayer height are laid perpendicular to the off direction, although those perpendicular to [11 (2) over bar 0] are apt to decompose into three bilayer or less. Formation mechanism of unit-cell-height steps is discussed based on consideration of bond configuration at step edges. (C) 2000 American Institute of Physics. [S0003-6951(00)01623-5].