Structural analysis of vicinal Si(1 1 0) surfaces with various off-angles

We have investigated vicinal Si(1 1 0) surfaces with various off-angles using atomic force microscopy and transmission electron microscopy. The vicinal surfaces were tilted from the exact Si(1 1 0) surfaces by 2–8° toward the [11¯0] direction. Peculiar surface structures were observed with a strong dependence on the off-angles, including triangular pyramid-like structures on 2° off surfaces, line structures on 4° and 8° off surfaces and nanometer-height mountain structures on 6° off surfaces. The structures on 2° and 4° off surfaces were based on the stair-like structure composed of Si(1 1 0) terraces and monolayer steps. On the other hand, 6° and 8° off surfaces could be understood in terms of Si(1 1 0) terraces and bunched steps.