Early stages of pulsed-laser growth of silicon microcolumns and microcones in air and SF6

摘要: Dense arrays of high-aspect-ratio silicon microcolumns and microcones are formed by cumulative nanosecond pulsed excimer laser irradiation single-crystal in oxidizing atmospheres such as air SF6. Growth surface microstructures requires a redeposition model also involves elements self-organization. The shape the microstructures, i.e., straight columns vs. steeply sloping cones connecting walls, is governed type concentration species, e.g., oxygen fluorine. believed to occur “catalyst-free” VLS (vapor–liquid–solid) mechanism that repetitive melting tips columns/cones deposition there ablated flux Si-containing vapor. Results presented new investigation how different final or joined walls nucleate develop. changes morphology were systematically determined compared number KrF (248 nm) shots was increased from 25 several thousand both experiments SF6 reveal significant differences initial cracking pattern formation. Consequently, local protrusions first produced column cone/wall growth initiated processes at rates. Differences spatial organization apparent.