Formation of double-monolayer-height islands on a Si(001) surface by alternating current heating in molecular beam epitaxy

Molecular beam epitaxy (MBE) of Si atoms onto a Si(001) 1x2 surface is inve stigated using reflection electron microscopy. A 1x2 surface with wide 1x2 and narrow 2x1 terraces is prepared by passing a direct current from the do wn side to the up side at the surface steps. After sample heating to 900 de grees C using an alternating current without deposited Si atoms, the 1x2 su rface changes to a double-domain surface, where the width of the 2x1 terrac es is approximately equal to that of the 1x2 terraces. With MBE, however, t he 1x2 surface remains the 1x2 surface, and the double-monolayer-height isl ands with an approximately circular shape are stably formed on it. (c) 1999 American Institute of Physics. [S0003-6951(99)03724-9].