Polycrystalline Germanium and Silicon-Germanium Alloys on Plastic for Realization of Thin-Film Transistors

Abstract

AbstractDevice-quality polycrystalline Ge layers have been grown on flexible poly-ethylene terephthalate (PET) substrates by means of stress-assisted Cu-induced crystallization at temperatures as low as 130°C and employed for fabrication of depletion-mode poly-Ge thin-film transistors (TFTs). These TFTs show an ON/OFF ratio of 104and an effective hole mobility of 110 cm2/Vs. The stress-assisted crystallization technique has been extended to crystallize SiGe alloys at low temperatures for possible fabrication of poly-SiGe TFTs on plastic. As a result, poly-Ge seeded poly-crystalline SiGe layers with 40% Si content are grown at a low annealing temperature of 180°C in the presence of 0.05% equivalent compressive strain.