Sublimation of a heavily boron-doped Si(111) surface

We investigated sublimation of a heavily boron-doped Si(lll) surface in com parison with that of a normal Si(lll) surface in ultrahigh vacuum. Step spa cing during step-flow sublimation is analyzed as a measure of the adatom di ffusion length using >50-mu m-wide (111) planes created at the bottom of cr aters. On the heavily doped 1x1 surface, the step spacing is smaller and th e step-spacing transition (or "incomplete surface melting'' transition) tem perature is 60 degrees higher than those on the normal 1x1 surface. These r esults are interpreted in terms of the effect of boron at S-5 substitutiona l sites. Below 1100 degrees C, the sublimation of heavily doped surface on the wide terrace turns into a two-dimensional vacancy-island nucleation mod e from step-flow sublimation observed above 1100 degrees C. [S0163-1829(98) 05243-6].