Arrangement of silicon nano-dots along step edges of a Si(111) surface: STM investigation

Arrangement of silicon nano-dots along the step edges of a vicinal Si(111) surface was achieved. Silicon nitride islands were formed on a vicinal Si(111) surface, which was 1° off toward the [112] direction, via a thermal nitridation reaction using N₂ gas. On this nitrided surface, oxygen gas was dosed to induce a local selective etching of the bare silicon area. The resultant surface showed a one-dimensional arrangement of silicon nano-dots along the step edges of the silicon surface. The lateral size of the dot in the direction perpendicular to the step edges was restricted to the terrace width of the stepped Si(111) surface. This is explained in terms of the preferential growth of silicon nitride islands on the surface step edges, resulting in the apparent alignment of silicon nano-dots along the step edges of the vicinal Si(111) surface.