International Conference on Solid State Devices and Materials

Thin poly-Ge films (thickness: < 50 nm) are attractive channel materials for high performance fully-depleted thin-film transistors. However, carrier mobility in poly-Ge films decreases with decreasing film thickness. To solve this problem, we developed the interface-modulated solid-phase crystallization of Ge films combined with Sn-doping and Si-capping. This enables formation of thin poly-Ge films having high carrier mobility. However, carrier concentration is also increased. To decrease the carrier concentration, we have examined post-annealing (PA). It is clarified that PA after removing the Si cap layers enables decrease in the carrier concentration with keeping the high carrier mobility.