Structural Changes in SiGe/Si Layers induced by Fast Crystallization

Abstract

SiGe alloys are promising for employment in nano-electronics, infrared photodetectors and next generation of solar cells. The present short review surveys the new field of SiGe transient processing dealing with unusual phase transitions, segregation and structural changes. Fast segregation leads to constitutional supercooling in the melt near the front of crystallization which then results in faceting of the liquid-solid interface followed by generation of extended defects, spatial variation of the composition and formation of nano-cellular structure. Faceting of the interface and formation of cellular structure depends strongly on SiGe alloy composition and on the velocity of melt-solid interface (solidification). Therefore fast processing might become an alternative and very promising pathway for the treatment of SiGe layers and nanostructures. The following issues are shortly reviewed: Segregation of Ge to nanometer-scale cellular network and islands: effect of SiGe composition and crystallization velocity; Morphology and atomic structure of swift heavy ion-induced discontinuous tracks in SiGe alloy layers as a result of fast segregation; Pulsed laser modification of Ge and GeSn nanodots; Laser-induced melting and recrystallization of polycrystalline Ge layer.