Epitaxial explosive crystallization of amorphous silicon

Abstract
It is shown that amorphous silicon can be transformed to monocrystalline silicon via an explosive epitaxial crystallization process induced by pulsed laser irradiation. 370-nm-thick amorphous Si layers, buried beneath a 130-nm-thick crystalline surface layer, were irradiated with a 32 ns ruby laser pulse. Real-time reflectivity measurements indicate that internal melting can be initiated at the amorphous-crystalline interface, immediately followed by explosive crystallization of the buried amorphous Si layer. Channeling and cross-sectional transmission electron microscopy reveal that explosive crystallization proceeds epitaxially with formation of twins extending into the sample. The crystal growth velocity is determined to be 16.2±1.2 m/s, close to the fundamental limit for crystalline ordering at a liquid Si/Si(100) interface.