Amorphous Si/(Ge+Au) artificial superlattice thin films were fabricated and their thermoelectric properties were investigated. With thermal annealing, the artificial superlattice structure defused easily and recrystallization started. The recrystallization process progressed gradually, even after superlattice structure collapsed. When optimum Au concentration and annealing temperature, nanocrystals of around 10 nm diameter (nano-dots) were segregated in quasi-stable condition by the metal induced recrystallization effects of Au. The extra-ordinary high thermoelectric power was observed only when nano-dots were present. The quantum size effect of the nano-dots was responsible for the high thermoelectric power of SiGe-based thin films.