Surface structure of self-organized sapphire (0001) substrates with various inclined angles

We studied the Surface Structure Of Self-organized sapphire (000 1) substrates with various inclined angles. using an atomic force microscope (AFM) in UHV. The self-organized surface structure strongly depended on annealing condition, inclined angle and inclined direction. We could successfully produce a highly self-organized Step Structure by choosing suitable values of these parameters. The surface of the self-organized inclined substrates was characterized by step and terraces. The morphology of step edges depends on the inclined direction of the substrate. In the case of the <1(1) over bar 00 > inclined direction, the step edges were faceted, and the faceted plane was the <2(11) over bar 00> plane. On the other hand, in the case of the <11(2) over bar 0 > inclined direction, the step edges were Straight. The distribution of step heights and ten-ace widths measured from AFM images are presented. The distribution of step heights had peaks corresponding to the unit cell of the sapphire crystal, while the terrace widths followed a normal distribution.