Comb-shape step formation on Si(001)-2 × 1 surface

Abstract

We report about the formation of grating-like 2 × 1 and 1 × 2 domain structures, where stripe-shape mounds and troughs with monoatomic step height difference appear alternately and cover the entire terrace part with quite uniform periodicity, on Si(001) wafer which has very small miscut angle and high P dopant concentration. The mechanism of the formation of such stripe-shape domains was considered as the combination of the very wide terrace width, and the segregation of the dopant P in the surface cleaning process. The former is due to the expansion of 2 × 1 single domain which contains surface tensile stress perpendicular to the dimer rows formed by dimers. The latter increased the surface stresses by replacing the SiSi dimers with PP or PSi dimers which have a shorter dimer bond length.