We have used low energy electron microscopy (LEEM) to study in real time the self‑assembly of periodic stripe arrays on atomically flat Si(100) with high boron doping. Stripes consist of extremely elongated vacancy islands of single atomic height, formed at ~900ºC, confined in micrometer-sized pits. We have been able to create highly ordered arrays of straight, parallel stripes (in pits of up to ~8 μm in size) formed by allowing various defects to heal over relatively long periods of time. To allow this equilibration to occur, sublimation was compensated for by an external Si doser, allowing observation of stripe evolution over the course of hours, with no net loss or gain of Si from the area of interest. Equilibrium stripes are very uniform in width and periodicity, and exhibit the greatest stability at 0.5 monolayer coverage. Observed stripe formation and ordering mechanisms include spontaneous nucleation and growth of new stripes, longitudinal splitting, as well as coarsening due to surface diffusion. Stripe periodicity depends on temperature, allowing for control of this property. Stripes form in a temperature range of ~100C, outside of which they assume the familiar shape of elongated islands. Stripe order can be preserved to room temperature by quenching.

Work supported by the U.S. DOE, Office of BES, DMSE. Sandia is operated by Sandia Corporation, a Lockheed Martin Company, for the U.S. DOE’s NNSA under Contract No. DE-AC04-94AL85000.